水畑 穣 | ![]() |
ミズハタ ミノル | |
大学院工学研究科 応用化学専攻 | |
教授 | |
化学関係 |
2017年06月 日本セラミックス協会, 第71回(平成28年度)日本セラミックス協会学術賞, 水溶液反応による酸化物析出反応プロセスの解明と電気化学材料への展開
国内学会・会議・シンポジウム等の賞
2016年08月 The 4th International Symposium on Rare Earth Resource Utilization and The 7th International Symposium on Functional Materials, Functional Materials Scientist Award, Fabrication and the Reaction Process of Liquid Phase Deposition
In recognition of excellent research performance in the field of functional materials, 日本国国際学会・会議・シンポジウム等の賞
2005年04月 電気化学会, 電気化学会論文賞, Fabrication of Metal-oxide Nanoparticles by the Liquid Phase Deposition Method in the Heterogeneous System
2003年09月 日本化学会コロイドおよび界面化学部会, 第56回コロイド及び界面化学討論会ポスター賞, 発光性分子に対するAgナノ粒子の発光増強剤および消光剤としての機能
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We experimentally and computationally investigated the Ca substitution effect on the electrochemical performance of P3-NaxCoO2. The cycle performance of Ca-substituted Na(x)Ca(0.04)CoO(2)was effectively improved due to its better crystallinity retention after charging. Our DFT calculations suggested that the presence of Ca(2+)ions in Na sites kinetically mitigates phase transition.
ROYAL SOC CHEMISTRY, 2020年07月, CHEMICAL COMMUNICATIONS, 56 (58), 8107 - 8110, 英語[査読有り]
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The deterioration mechanisms of a Ni–metal hydride (Ni–MH) battery system during operation is investigated. A decrease of the discharge voltage is observed at the early stage of the cycle, which indicates the possible occurrence of an unexpected system shutdown of the battery at low state of charge. Cyclic voltammetry and surface examination are used to investigate the causes of this phenomenon. The elution of elements such as Al and Mn from the metal hydride negative electrodes is shown to affect the oxidation/reduction behavior of Co, the conductive material of the positive electrode. Furthermore, the possible methods to strengthen the conductive network of Co, including pretreatment of the positive electrode, addition of conductive material, and precipitation of the elution elements as insoluble compounds to reduce their effect are also investigated. By combining these strategies, deterioration of the conductive network can be prevented in the early stage.
Elsevier, 2018年06月01日, Journal of Power Sources, 388, 45 - 51, 英語[査読有り]
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The Ni-Al layered double hydroxide (Ni-Al LDH) as an anode in nickel-metal hydride batteries is synthesized by liquid phase deposition (LPD) and the interlayer distance of the Ni-Al LDH is enlarged by the anionic exchanges from F− form to halide anion forms, oxo anion forms, complex anion forms, and surface-active agent anion forms, namely, ca. from 320 p.m. to a maximum of 2500 p.m. Then, we fabricate electrodes from the anion-exchanged LDH and study the relations between interlayer distance and internal resistance. The interlayer distances of the Ni-Al LDH, which are calculated from d003 increase with the diameter of the intercalated anions. The interlayer distance of the LDH depends on the molecular shape and size of the intercalated anions. The charge transfer resistance(Rct) decreases by half when the LDH interlayer distance increases to about 400 p.m., and the activation energy for charge transfer(ΔEa) also decreases with increasing LDH interlayer distance. Furthermore, the electron transfer and the ion transport between the collector (i.e., Ni foam) and the active material especially contribute to the decrease of Rct and ΔEa of the electrode compared with those between the conductive assistant (i.e., carbon black powder).
Elsevier Ltd, 2018年04月20日, Electrochimica Acta, 270, 395 - 401, 英語[査読有り]
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研究論文(国際会議プロシーディングス)
An ionic liquid system based on two amide anions bis(fluorosulfonyl)amide anion (FSA-) and bis(trifluoromethanesulfonyl) amide anion (TFSA-), with a quaternary ammonium cation N,N,N-trimethyl-N-propylammonium cation (TMPA+), was investigated over entire composition range. The system showed the binary phase diagram and the eutectic point was 5.5°C around the anion ratio of 1:2 (FSA-: TFSA-). Polymorphic behavior of solidified ionic liquid was observed by X-ray diffraction (XRD) and discussed comparing with ionic liquids composed of other anion (fluorosulfonyl) (trifluoromethylslufonyl)amide anion (FTA-) or tetrafluoroborate anion (BF4 -). In addition, the phase diagram of the ionic liquid system containing lithium cation with binary anion was confirmed. Raman spectroscopy suggested that lithium cation interacts more preferentially with TFSA- than FSA-.
電気化学会, 2018年, Electrochemistry, 86 (2), 92 - 98, 英語[査読有り]
研究論文(学術雑誌)
Supramolecular hydrogels are expected to have applications as novel soft materials in various fields owing to their designable functional properties. Herein, we developed an in situ synthesis of supramolecular hydrogelators, which can trigger gelation of an aqueous solution without the need for temperature change. This was achieved by mixing two precursors, which induced the synthesis of a supramolecular gelator and its instantaneous self-assembly into nanofibers. We then performed the in situ synthesis of this supramolecular gelator at an oil/water interface to produce nanofibers that covered the surfaces of the oil droplets (nanofiber-stabilized oil droplets). External stimuli induced fusion of the droplets owing to disassembly of the gelator molecules. Finally, we demonstrated that this stimuli-induced droplet fusion triggered a synthetic reaction within the droplets. This means that the confined nanofiber-stabilized droplets can be utilized as stimuli-responsive microreactors.
WILEY-V C H VERLAG GMBH, 2017年08月, ANGEWANDTE CHEMIE-INTERNATIONAL EDITION, 56 (32), 9410 - 9414, 英語[査読有り]
研究論文(学術雑誌)
We report palmitoylated amino acids (glycine, l-valine, l-isoleucine, l-aspartic acid, l-glutamic acid, l-methionine, l-phenylalanine, l-lysine) as low-molecular-weight gelators for ionic liquids (ILs). The palmitoylated amino acids gelate ammonium- and imidazolium-based ILs, at gelation concentrations of 0.3-1.6 wt.%, despite their simple molecular structures. Eight types of gelators are synthesized, with palmitoylated methionine (Pal-Met) and palmitoylated phenylalanine (Pal-Phe) exhibiting high gelation ability toward the tested ILs. Scanning electron microscopy and confocal laser scanning microscopy observations suggest that the gelator molecules self-assemble into nanofibers within the ILs, which leads to gelation. The ionogels exhibit reversible thermal transition and viscoelastic properties, which are typical of gels. Fourier-transform infrared spectra recorded at various temperatures reveal that hydrogen bonding and van der Waals interactions between gelator molecules are important in the self-assembly. Incorporating gelators of varying concentrations do not affect the intrinsic conductivities of the ILs.
SPRINGER, 2017年07月, COLLOID AND POLYMER SCIENCE, 295 (7), 1109 - 1116, 英語[査読有り]
研究論文(学術雑誌)
The pretreatment to modify the valence of cobalt by discharging at 0.2 C rate for 7.5 h before the first initial activation charge process is effective in improving the surface electronic conductivity among fine particles of positive electrode active materials. The discharge curves indicate the same locus within 1800 cycles, and the capacity of the pretreated battery is stable for over 4000 cycles. However, in-situ cell pretreatment with constant current has negative influence on other components. During the constant current pretreatment, the cell voltage rapidly falls to -0.5 V in the first 10 s of in-situ pretreatment. Therefore, we investigate the pretreatment by supplying a constant voltage to the battery instead of a constant current, and find the effective condition to improve the electrochemical performance and not to have any influence on other components of the battery. (C) 2017 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2017年06月, JOURNAL OF POWER SOURCES, 352, 143 - 148, 英語[査読有り]
研究論文(学術雑誌)
In this study, quantitative nuclear magnetic resonance (qNMR) spectroscopy of quadrupolar nuclei has been established. The complicated hydrolysis behavior of the Al3+ ion, which causes fish poisoning and inhibits the growth of plants in environmental water, was clarified by Al-27 qNMR spectroscopy. Highly accurate simultaneous multicomponent quantitative analysis of various hydrolyzed forms of the Al ion was achieved in a non-destructive manner. The calibration curve of the external standard aqueous Al(NO3)(3) solution showed excellent linearity over a very wide concentration range from 1 x 10(-4) to 1 mol L-1 (an increase in concentration of 10 000 times), with a simple experimental and analytical procedure. Furthermore, the weaknesses of the conventional Ferron assay and the advantages of Al-27 qNMR spectroscopy were considered. The quantitative determination error for the free [Al(H2O)(6)](3)(+) ion and the trinuclear complex, which has a high complexation rate, is higher in the Ferron assay than in the Al-27 qNMR technique. The concentrations of four Al species were directly determined by Al-27 qNMR, namely, free [Al(H2O)(6)](3)(+), the trinuclear complex, Al(OH)(4)(-), and tridecameric hydrolyzed Al, which has a Keggin structure. The concentration of the tridecamer rapidly increased until 100 min after NaOH addition, and showed a local maximum after 1 week. In addition, the concentration of colloidal Al hydroxide, which cannot be detected by NMR spectroscopy, was determined by numerical analysis. This species was generated in the initial stage of reaction, and then the tridecamer formed very slowly.
ROYAL SOC CHEMISTRY, 2017年05月, ANALYST, 142 (10), 1790 - 1799, 英語[査読有り]
研究論文(学術雑誌)
Dynamic properties related to1H NMR relaxation in SiO2 fine powder/non-aqueous LiClO4 solution was measured for using propylene carbonate (PC) and PC-1,2-dimethoxyethane (DME). The influence of solid phase and variation of effect of DME on ionic mobility is also discussed. For1H NMR spectra of PC-DME binary solution, adding of SiO2 powder caused the broadening of NMR signal of1H in PC and DME molecules. In pure PC-DME system, since DME is preferentially affected by solids rather than PC, as the ratio of DME increased, values of solvent molecules detected by NMR decreased. In 1 mol/L LiClO4/PC-DME system, as the ratio of DME in solution was higher, The interaction between the PC and the Li+ ion is weakened by the decrease of the dissociation degree, and the mobility of the PC was restored.
Electrochemical Society Inc., 2017年, ECS Transactions, 80 (10), 1381 - 1389, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Properties of concentrated ZnSO4 aqueous solutions coexisting with metal oxide nanoparticles were observed. Raman spectroscopy indicated that ion pair forming tendencies was enhanced in the vicinity of silica nanoparticles which have hydrophilic groups. Zn2+ is supposed not to make sufficient hydration sphere and tend to make contact ion pair due to sharing water molecules with hydrophilic solid surface. Alumina nanoparticles exhibited strong effect on 1H relaxation than silica nanoparticles. The salt concentration dependences of 1H relaxation time and pH of aqueous solution suggested that the effects from solid phase on coexisting liquid phase were affected by liquid property in itself.
Electrochemical Society Inc., 2017年, ECS Transactions, 80 (10), 1459 - 1470, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Carbon coated porous silicon with various pore sizes as a model of porous electrode was prepared for Electric double layered capacitors (EDLCs). Each carbon coated PSi has a diameter ranged from 7 to 72 nm. The specific capacitance was influenced the diameter of main chain observed surface SEM images. The calculated capacity of each electrode depends on the pore distribution which showed the overlapping the electronic double layer.
Electrochemical Society Inc., 2017年, ECS Transactions, 80 (10), 1399 - 1405, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Etching of commercial pure titanium (CP-Ti) covered with metal oxide scale transferred to the surface from roller mills like those used for steel refining was investigated based on potentiodynamic polarization measurements and quantitative analysis of metal dissolved in HF or HF-HNO3. CP-Ti prepared by an industrial titanium supplier, titanium plate with scale (S-Ti), and annealed and pickled titanium (AP-Ti) were examined. The titanium substrate under the scale layer immediately dissolved in HF solution of concentration 1.0 mol.L-1. The etching behavior was examined in detail by electrochemical analysis in dilute HF. At HF concentrations less than 0.1 mol.L-1, the oxidized layer of S-Ti remained. X-ray photoelectron spectroscopy was used to identify the major components of the S-Ti surface, such as copper and iron impurities. In HF-HNO3 solution, the scale was removed slowly, even at high HF concentrations. The amounts of dissolved titanium indicated that calcium on the titanium metal surface increased the etching rate, and the minimum apparent activation energies,.Ea, of the etching reactions were observed at a concentration of 0.0316 mol.L-1 HF aq. for S-Ti and AP-Ti because of the trade-off between the HF activity and ionic dissociation. Etching of CP-Ti began with dissolution of the passive layer of titanium; corrosion of S-Ti was the result of destruction of the titanium oxide layer by F-and dissolution of the pure titanium substrate. The etching behavior of S-Ti at high HF concentrations suggested that scale peeling by substrate etching is a promising method for efficient scale removal. The HNO3 concentration had little effect on the anodic polarization curves of CP-Ti. This is attributed to the presence of a stable oxide layer on the titanium metal. We investigated the details of the S-Ti etching mechanism in HF-HNO3 for efficient scale removal.
JAPAN INST METALS, 2017年, MATERIALS TRANSACTIONS, 58 (9), 1280 - 1289, 英語[査読有り]
研究論文(学術雑誌)
Lithium orthosilicate (Li4SiO4) is a ceramic CO2 absorbent with a large absorptive capacity (36.7 wt.%) and heat resistance properties. Li4SiO4 has applications as a separator in molten carbonate fuel cells, and as a direct CO2 absorbent in large-scale emission sources such as thermal power stations. The absorption and desorption reaction equilibrium temperature of Li4SiO4 is around 993 K. This study investigates the CO2 absorption behavior of Li4SiO4 at lower temperatures. Samples whose surfaces were modified with ball milling under an Ar atmosphere exhibited increased Brunauer-Emmett-Teller surface areas. Electron spin resonance (ESR) spectroscopy indicated an increase in the content of Si dangling bonds upon ball milling. Thermogravimetric-differential thermal analysis indicated two different CO2 absorption processes: chemisorption at the Li4SiO4 surface at temperatures below 773 K; bulk diffusion at temperatures above 773 K. Isothermal analysis indicated that ball milling and adding K2CO3 decreased the activation free energy. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2016年11月, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 41 (41), 18893 - 18899, 英語[査読有り]
研究論文(学術雑誌)
A ZnS thin film was electrodeposited on the surface of nanopores of porous silicon (PSi) without plugging of the nanopores. And the optical properties of the ZnS/PSi composites were investigated. The PSi was fabricated by anodization of n-Si (100) wafer in HF/EtOH/H2O solution under constant current conditions. The pore diameter and the porous layer depth of the PSi were 20-80 nm and 8-50 mm, respectively, and they are controlled by variation of the HF concentration and anodization time. Electrodeposition proceeded on the surface of the nanopores (pore diameter, 80 nm) of the PSi under galvanostatic conditions of 0.44-8.85 mA/cm(2) and the aqueous electrolyte solution contained ZnSO4, Na2S2O3 and glycerol. The deposited ZnS plugged the nanopores at high current density, whereas at low current density, ZnS was deposited on the nanopore wall without plugging. The photoluminescence (PL) spectra due to the ZnS/PSi composites showed two separate peaks at 430 nm and 530 nm. The PL intensity decreased with increased current density because of the segregation of ZnS on the upper parts of the PSi nanopores. The PL intensity was also enhanced owing to the large surface area of the PSi. (C) 2016 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2016年05月, ELECTROCHIMICA ACTA, 201, 86 - 95, 英語[査読有り]
研究論文(学術雑誌)
A porous Si/cerium oxide composite (PSi/ CeO2) was synthesized by electrodeposition of CeO2 via anodic oxidation on PSi. The PSi photoluminescence (PL) was enhanced. The anodically oxidized PSi substrates in HF solution had macropores (diameter 2 mu m), mesopores (diameter 15 nm), and micropores (diameter less than 4 nm). Emission at 700 nm from microporous PSi (microPSi) was observed under ultraviolet irradiation. Transmission electron microscopy showed that in microPSi/CeO2, the oxide was infiltrated into microPSi by anodization. The deposited amount of CeO2 depended on the reaction time, applied voltage, temperature, and reaction species concentrations in anodization. Emission by microPSi/CeO2 at 650 nm was observed; the PL intensity was higher (about 10-30 times) than that of PSi because of energy transfer from CeO2 to nanosized Si in porous layers produced by HF etching. The lifetime of the PL of microPSi/CeO2 was longer than that of microPSi. Excitation spectra of microPSi/CeO2 at 650 nm and diffuse-reflectance spectra showed that the excitation peak for microPSi/CeO2 was similar to the absorbance of CeO2, and excitation of microPSi/CeO2 gave two peaks, at 3.7 and 4.4 eV; these peaks originated from the absorptions of CeO2 and Si nanocrystals. The PL of PSi was enhanced in microPSi/CeO2 because of efficient energy transfer from CeO2 to the Si nanocrystal.
SPRINGER, 2016年02月, APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING, 122 (2), 1 - 12, 英語[査読有り]
研究論文(学術雑誌)
In this study, the non-Aqueous LiCIO4 solution mixed with fumed silica as model system of LIBs was applied, and the dynamic properties and influences which solvent molecules received from solid phase or Li+ ion in using the NMR spectroscopy and the relaxation time (T1, T2) measurements were evaluated. The NMR signal of 1H in PC molecules is influenced by coexisting solid phase in L1CIO4-PC solution /oxide powder. The dynamic property of the PC molecules drastically decreased in comparison with the system of the liquid only system. In IR spectra of PC/Alumina systems, the vibration in higher wavenumber range are predominantly observed due to indirect electron-donation from solid surface. The signal intensity depends on influenced liquid content from solid phase. Especially, the LiClo4-PC solution /alumina systems, the intensity is abruptly decreased due to widely spread influences of solid phases. Moreover, the influence from the solid phase to the PC molecules is much smaller than the water molecules from the 1H spin-spin relaxation time (T1). As for the electrolyte concentration dependence, PC system was more remarkable than the water solution system, namely the network structure of the whole PC solvent is greatly affected by the addition of the Li+ ion, and it is thought that relaxation time largely decreased.
Electrochemical Society Inc., 2016年, ECS Transactions, 75 (19), 1 - 9, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Ni-Al layered double hydroxides (LDHs) are used as anodes in nickel- metal hydride batteries because of their good electrochemical properties, in turn because of the structural stability of the alkali electrolyte and the minimal volume change during charging and discharging. LDHs can experience interlayer anionic exchange and can change their interlayer distance by anionic exchange. In this study, we synthesized an Ni-Al LDH by liquid phase deposition (LPD) and increased its interlayer distance by anionic exchange. Then, we fabricated electrodes from the anion-exchanged LDH and studied the relations between interlayer distance and internal resistance. The interlayer distances of the Ni-Al LDH, calculated from dm, increased with the diameter of the intercalated anions. The interlayer distance of the LDH depended on the molecular shape and size of the intercalated anions. The charge transfer resistance decreased when the LDH interlayer distance increased to about 300-400 pm, and the activation energy for charge transfer decreased with increasing LDH interlayer distance.
Electrochemical Society Inc., 2016年, ECS Transactions, 75 (19), 11 - 20, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The dependence of polyelectrolyte characteristics on the number of phosphate groups in a series of polyphosphates was clarified by potentiometric titration and Na-23 nuclear magnetic resonance using the Donnan model. Ca2+ ion binding to various polyphosphates was consistently inhibited as supporting electrolyte concentration increased. The electrostatic interactions between polyions and counterions, which is peculiar to polyelectrolytes, was enhanced by an increase in the number of phosphate groups. The polyelectrolyte characteristics increased non-monotonically with the number of phosphate groups that constituted the molecules, that is, (1) gradual emergence with three or four phosphate groups, (2) marked strengthening from four to eight phosphate groups, and (3) saturation with eight or more phosphate groups. The characteristics of polyelectrolyte molecules comprising eight or more phosphate groups were independent of the degree of polymerization. These interesting behaviors were observed to be closely similar using two quite different experimental techniques, electrochemical titration and nuclear magnetic resonance. (C) 2015 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2015年11月, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 484, 153 - 163, 英語[査読有り]
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We prepared a heterogeneous double-network (DN) ionogel containing a low-molecular-weight gelator network and a polymer network that can exhibit high ionic conductivity and high mechanical strength. An imidazolium-based ionic liquid was first gelated by the molecular self-assembly of a low-molecular-weight gelator (benzenetricarboxamide derivative), and methyl methacrylate was polymerized with a cross-linker to form a cross-linked poly(methyl methacrylate) (PMMA) network within the ionogel. Microscopic observation and calorimetric measurement revealed that the fibrous network of the low-molecular-weight gelator was maintained in the DN ionogel. The PMMA network strengthened the ionogel of the low-molecular-weight gelator and allowed us to handle the ionogel using tweezers. The orthogonal DNs produced ionogels with a broad range of storage elastic moduli. DN ionogels with low PMMA concentrations exhibited high ionic conductivity that was comparable to that of a neat ionic liquid. The present study demonstrates that the ionic conductivities of the DN and single-network, low-molecular-weight gelator or polymer ionogels strongly depended on their storage elastic moduli.
AMER CHEMICAL SOC, 2015年10月, ACS APPLIED MATERIALS & INTERFACES, 7 (41), 23346 - 23352, 英語[査読有り]
研究論文(学術雑誌)
The direct synthesis of an Ni-Al layered double hydroxide (LDH) as the active material in an Ni-metal hydride secondary battery on an electron-conductive substrate was performed using liquid phase deposition method. A reduction in charge-transfer resistance was achieved by coating a Ni-Al LDH film on a Ni foam surface current collector, as a result of improved adhesion between the current collector and the active material. (C) The Electrochemical Society of Japan, All rights reserved.
電気化学会, 2015年10月, Electrochemistry, 83 (10), 803 - 806, 英語[査読有り]
研究論文(学術雑誌)
The effects of the molecular structure and solution pH on compounds prone to lactam lactim tautomerism have been evaluated by N-15 NMR spectroscopy. The lactam-lactim tautomerism activities of cP(3)O(6)(NH)(3)(3-) and cP(4)O(8)(NH)(4)(4-) showed a significant pH dependence, with the process being inactivated under alkaline conditions because of the decrease in the number of hydrogen atoms by the deprotonation of the anions. The tautomerism was activated under the acidic conditions by the increase in the number of dissociative hydrogen atoms resulting from the protonation of the anions. cP(3)O(6)(NH)(3)(3-) has much more of a planar molecular structure than cP(4)O(8)(NH)(4)(4-), meaning that the hydrogen atoms in cP(3)O(6)(NH)(3)(3-) would be delocalized over the entire structure to a greater extent than those in cP(4)O(8)(NH)(4)(4-). This difference in the distribution of hydrogen atoms would result in the lactam lactim tautomerism activity of cP(3)O(6)(NH)(3)(3-) being higher than that of cP(4)O(8)(NH)(4)(4-). The results have shown that the following factors are critical to the achievement of an efficient anhydrous proton conductor: (1) the regular molecular arrangement of highly planar molecules; (2) the existence of a large number of dissociative protons in a molecule; and (3) a molecular structure with a small energy barrier for the structural rearrangement required of the tautomerism process.
American Chemical Society, 2015年09月, The Journal of Physical Chemistry B, 119 (37), 12289 - 12298, 英語[査読有り]
研究論文(学術雑誌)
The direct synthesis of the adhered Ni-Al LDH thin film onto the surface of electrically conductive substrates by the liquid phase deposition (LPD) reaction is carried out for the development of the positive electrode. The complexation and solution equilibria of the dissolved species in the LPD reaction have been clarified by a theoretical approach, and the LPD reaction conditions for the Ni-Al LDH depositions are shown to be optimized by controlling the fluoride ion concentration and the pH of the LPD reaction solutions. The yields of metal oxides and hydroxides by the LPD method are very sensitive to the supersaturation state of the hydroxide in the reaction solution. The surfaces of conductive substrates are completely covered by the minute mesh-like Ni-Al LDH thin film; furthermore, there is no gap between the surfaces of conductive substrates and the deposited Ni-Al LDH thin film. The active material layer thickness was able to be controlled within the range from 100 nm to 1 mu m by the LPD reaction time. The high-crystallinity and the arbitrary-thickness thin films on the conductive substrate surface will be beneficial for the interface control of charge transfer reaction fields and the internal resistance reduction of various secondary batteries.
AMER CHEMICAL SOC, 2015年08月, ACS APPLIED MATERIALS & INTERFACES, 7 (31), 17188 - 17198, 英語[査読有り]
研究論文(学術雑誌)
© 2015 IOP Publishing Ltd. This work describes a room-temperature imprinting of nanoporous glass prepared by selective chemical etching of phase-separated glass. A highly porous (58%) and highly transparent (>90%) porous glass layer can be formed on a transparent phase-separated glass substrate. It is shown that the lateral resolution of the imprinting is a few tens of nanometers. As the porosity increases, the imprint depth increases and reaches up to 90% of the height of the mold pattern. The porous glass has a wider transmittance window (300-2700 nm) and a higher thermal durability (∼500 °C) than other materials used for imprinting. The technique has various potential applications such as diffraction optical elements, waveguides, biosensors, and microfluidic devices.
2015年06月26日, Nanotechnology, 26 (25), 1 - 8, 英語[査読有り]
研究論文(学術雑誌)
TiO2/porous Si (PSi) nanocomposites were fabricated by liquid-phase deposition with anodization of PSI. Scanning electron microscopy-energy-dispersive X-ray spectroscopy showed that TiO2 was only deposited in the fine pores of anodized PSi (ca. 7.4 nm) when the PSi surface was anodized in the presence of Ti ions as F- scavengers. The TiO2/PSi nanocomposites were fabricated by anodization of PSi in a H2TiF6 electrolyte at a constant potential. The amount of Ti deposited was maximum at 300 mV vs. Ag/AgCl electrode, and the deposition process was controlled by varying the applied potential for PSi anodization. The charge/discharge capacities of the fabricated TiO2/PSi nanocomposites as Li-ion battery anodes were determined. Improvements in the charge/discharge capacity were achieved by improving the PSi wettability by TiO2 deposition and activation of Si on the surface of the anodized PSi fine pores. TiO2/PSi fabricated by anodization maintained a high charge/discharge capacity without rapid degradation, because SiO2, which causes rapid degradation of the charge/discharge capacity, was reduced by Li metal. (C) 2014 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE, 2015年06月, Journal of Fluorine Chemistry, 174, 62 - 69, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(国際会議プロシーディングス)
Na-23, Cl-35, Br-81, and Rb-87 NMR have been applied to clarify the influence of electrostatic and hydrophobic interactions on the counterion binding equilibria of weakly acidic and basic polyelectrolytes with negatively and positively charged polyions, respectively. Na+ and Rb+ ions capable of binding to weakly acidic polymers (i.e., polyacrylate acid (PAA)), and Cl- and Br- ions capable of binding to weakly basic polymers (i.e., poly(N-vinylimidazole) (PVIm) and polyallylamine (PAAm)) were used as representative examples to measure these interactions. The results revealed that the longitudinal and transverse NMR relaxation rates of the Cl-, Br- and the Rb+ counterions in the PVIm and PAA systems were faster than those of free Cl-, Br- and Rb+ ions when the polyions were completely neutralized. The binding interactions between the Cl-, Br- and the Rb+ ions and PVIm and PAA were found to be hydrophobic in nature because the magnitudes of these effects were found to be dependent on the hydrophobicities of the polyelectrolytes and the counterions. Although a slight hydrophobic interaction was detected between the Rb+ ions and PAA, where the degree of neutralization of the polyacid (alpha) was 1, Na+ ions also started to bind to PAA at a = 0.65, where the linear charge density corresponded to the Bjerrum length. (C) 2015 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2015年04月, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 471, 1 - 10, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
The synthesis and isolation of the sodium salt of cyclo-tri-mu-imidotetraphosphate, i.e. Na(4)cP(4)O(9)(NH)(3)center dot H2O, were achieved by the hydrolysis of Na(4)cP(4)O(6)(NH)(4)center dot 2H(2)O under very weak acidic conditions, i.e. using 0.2 mot L-1- propionic acid and the pH-controlled recrystatlization procedure. The purity of Na(4)cP(4)O(9)(NH)(3)center dot H2O was improved from 2% to 95% by the pH-controlled recrystallization only two times. The first protonation constants of a series of cyc/o-p-imidotetraphosphate anions, i.e. cP(4)O(12-n)(NH)(n)(4-) (n = 0, 2, 3, 4), were determined by potentiometric titration and 31P NMR chemical shift measurements in aqueous solution. Regardless of the paucity of the purity of trans-cP4010(NH)24anions, the protonation processes of all anions may be evaluated accurately without any previous purification, because the NMR signals corresponding to cP(4)O(12-n)(NH)(n)(4-) (n = 0, 2, 3, 4) anions are well resolved. The logarithmic first protonation constants increase with a "linear" increase in the number of imino groups which constitute the tigand molecules. Macroscopic protonation reactions could be divided into three microscopic protonation processes for -0-P02-0-, -O--P02-NH--, and -NH-P02-NHgroups. The basicity of the -NH-P02-NH- group is especially high, because the detocalization of H+ ions by lactam-lactim tautomerism on the whole ring molecule of cP306(NH)3 and cP408(NH)4 enhances the protonation of these tigands. In addition, also the concurrent change observed in the 31P NMR chemical shift values of the phosphorus nuclei in the -0-P02-NH- and -NH-P02-NH- groups of cP(4)O(9)(NH)34- anions suggested the effect of the lactam-tactim tautomerism. The intrinsic 31P NMR chemical shifts for the central phosphorus nuclei for -0-P02-0-, -0-P02-NH-, and -NH-P02-NHgroups show a good proportional relationship with the number of nitrogen atoms bonded to the central phosphorus atoms. Two types of imino groups with mutually dissimilar chemical environments which are present in the Na(4)cP(4)O(9)(NH)(3) molecule, that is -O-PO2-NH-PO2-NH- and -NH-PO2-NH-P02NH-, brought about a two-stage pyrolytic elimination of imino groups from the initial stage of combustion over a wide temperature range.
Royal Society of Chemistry, 2014年08月, Dalton Tranactions, 43 (30), 11611 - 11623, 英語[査読有り]
研究論文(学術雑誌)
The electrical conductivity and Raman spectra of a Gd-doped ceria (Ce0.9Gd0.1O1.95)/molten (Li/Na)2CO3 composite were investigated concerning the electrolyte materials for intermediate temperature solid oxide fuel cells. Mixed samples of high-purity Ce0.9Gd0.1O1.95 powder and Li/Na binary carbonate (52:48wt%) were used. A higher electrical conductivity was obtained for the GDC/(Li0.52Na0.48)2CO3 composite than for α-Al2O3/(Li0.52Na0.48)2CO3, increasing with increasing temperature up to the melting point before the appearance of a linear Arrhenius plot. Even in a N2 or air gas flow (in which partial pressure of CO2, pCO2, was low) the weight loss caused by decomposition of CO3 ion based on the Lux-Flood equilibrium was rarely observed. Raman spectroscopic measurement of the system containing (Ce0.9Gd0.1O1.95)/molten (Li/Na)2CO3 indicated little change of the spectra. It was more stable than that for the system containing α-Al2O3.
Wiley Blackwell, 2014年06月23日, Molten Salts Chemistry and Technology, 535 - 541, 英語[査読有り]
論文集(書籍)内論文
The liquid-phase deposition (LPD) reaction and the deposition mechanisms for the preparation of hazy TiO2, transparent TiO2 and NH4TiOF3 films were investigated by quantitative F-19 NMR analysis. Contrary to the conventional understanding, the F-19 NMR spectra indicated that BF3(OH)(-) formed within a short reaction time, and the concentration of BF3(OH)(-) was always much higher than that of BF4- during the LPD reaction. Quantitative analysis also indicated that several types of titanium complexes coordinated by fluoride ions dissolved in the LPD reaction solutions, but they were not detected by F-19 NMR measurement because of rapid ligand substitution. A highly dense and transparent anatase TiO2 thin film was obtained at pH 3.5, and the growth of the particles comprising the films was accelerated by increasing the pH. Conversely, nucleation and crystal growth in the thin films were suppressed at lower pH. Furthermore, in the induction period of the LPD reaction, a shift of chemical equilibrium, which decreased the proton concentration, was observed, and we suggest that the necessary supersaturation state for nucleation is attained during this induction period.
AMER CHEMICAL SOC, 2014年06月, JOURNAL OF PHYSICAL CHEMISTRY C, 118 (22), 11964 - 11974, 英語[査読有り]
研究論文(学術雑誌)
The complexation behaviors of Be2+ with cyclo--imido triphosphate anions, cP(3)O(9-n)(NH)(n)(3-) (n=1, 2), have been investigated by both Be-9 and P-31 NMR techniques at -2.3 degrees C in order to clarify the coordination structures of the complexes. The spectra showed that cP(3)O(9-n)(NH)(n) (n=1, 2) ligands form ML, ML2, and M2L complexes with Be2+ ions, and the formation of complexes coordinating with nitrogen atoms of the cyclic framework in the ligand molecule has been excluded. These complexation trends are very similar to those of Be2+-cP(3)O(6)(NH)(3)(3-) system, which has been reported by us. The peak deconvolution of Be-9 NMR spectra made these beryllium complexes amenable to stability constant determinations. The stability constants of the complexes increase with an increase in the protonation constants of the ligands as the number of imino groups, which constitute the ligand molecules, is ascended. This increase is primarily attributable to the lower electronegativity of nitrogen atoms than oxygen atoms, which are directly bonded to central phosphorus atoms; moreover, tautomerism equilibrium in the entire of the imidopolyphosphate molecule is also responsible to the higher basicity. P-31 NMR spectra measured concurrently have verified the formation of the complexes estimated by the Be-9 NMR measurement. Intrinsic P-31 NMR chemical shift values of the phosphorus atoms belonging to ligand molecules complexed with Be2+ cations have been determined. Not only the protonation constants but also the stability constants of all Be2+ complexes increase approximately linearly with an increase in the number of imino groups. Copyright (c) 2013 John Wiley & Sons, Ltd.
WILEY-BLACKWELL, 2014年03月, Magnetic Resonance in Chemistry, 52 (3), 69 - 81, 英語[査読有り]
研究論文(学術雑誌)
We report the durability of the optimized nickel aluminum layered double hydroxide/carbon (Ni-Al LDH/C) composite prepared by liquid phase deposition (LPD) as cathode active materials in nickel metal hydride (Ni-MH) secondary battery. The positive electrode was used for charge discharge measurements under two different current: 5 mA for 300 cycles in half-cell conditions, and 5.8 mA for 569 cycles in battery regime, respectively. The optimized Ni-Al LDH/C composite exhibits a good lifespan and stability with the capacity retention above 380 mA h g(comp)(-1) over 869 cycles. Cyclic voltammetry shows that the alpha-Ni(OH)(2)/gamma-NiOOH redox reaction is maintained even after 869 cycles, and the higher current regime is beneficial in terms of materials utilization. X-ray diffraction (XRD) patterns of the cathode after charge and discharge confirms that the alpha-Ni(OH)(2)/gamma-NiOOH redox reaction occurs without any intermediate phase. (C) 2013 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2014年02月, JOURNAL OF POWER SOURCES, 247, 572 - 578, 英語[査読有り]
研究論文(学術雑誌)
Supramolecular gelators comprising 1,3,5-benzenetricarboxylic acids and amino acid methyl esters (glycine, L-alanine, L-valine, L-leucine, L-methionine, and L-phenylalanine) for ionic liquids were developed. Ten types of ionic liquids were gelated using the above-mentioned gelators at relatively low concentrations. Field emission-scanning electron microscopy and confocal laser scanning microscopy analyses revealed that these gelators self-assembled into an entangled fibrous structure in ionic liquids, leading to the gelation of the ionic liquids. Comparison studies, involving compounds analogous to the gelators, and Fourier transform infrared spectroscopy measurements suggested that hydrogen bonding played a key role in the self-assembly of the gelator molecules. The ionogels displayed reversible thermal transition characteristics and viscoelastic properties typical of a gel. The gelation of the ionic liquids studied under a wide range of gelator concentrations did not affect the intrinsic conductivity of the ionic liquids.
ROYAL SOC CHEMISTRY, 2014年, SOFT MATTER, 10 (7), 965 - 971, 英語[査読有り]
研究論文(学術雑誌)
The titanium oxide/PSi nanocomposite was fablicated by liquid phase deposition (LPD) method with applying anodic potential. Results of SEM-EDX measurement showed that TiO2 deposited into the fine pore (ca. 7.4 nm) only when oxidized PSi surface was used as F-scavenger or PSi was anodized under the existence of titanium ions. TiO2/PSi nanocomposite was fabricated by anodization of PSi in H2TiF6 electrolyte under constant potential. As the amount of Ti maximized at 300 mV vs. Ag/AgCl, deposition process can be controlled by applied potential in this method. The charge/discharge capacities were measured for fabricated TiO2/PSi as lithium-ion battery anode. The improvement of the capacity was derived from the increase in PSi wettability by TiO2 deposition and activation of silicon in fine structure. In addition, TiO2/PSi fabricated by anodization kept higher capacity without rapid degradation, because of free from SiO2.
ELECTROCHEMICAL SOC INC, 2014年, ELECTRODEPOSITION FOR MICRO- AND NANO- BATTERY MATERIALS, 61 (9), 9 - 20, 英語[査読有り]
研究論文(国際会議プロシーディングス)
High temperature Raman spectroscopy of Sm doped CeO2/carbonate composite was measured in order to discuss the interaction between carbonate ion and solid oxide electrolyte at an interface in Sm doped CeO2/carbonate LT-SOFC. In Raman spectra with temperature of carbonate breathing mode of NK in initial heating process, whereas separated v(1)(CO32-) bands assigned to Na2CO3 and K2CO3 are observed clearly at lower temperature, unifying of these bands was observed due to solid state migration of carbonates at temperature lower than eutectic point (983 K). Degree of migration is affected by apparent average thickness (AAT) and Sm amount in oxide. Solid state diffusion at temperature lower than eutectic point of carbonate mixture is assisted by coexistence of solid oxides.
ELECTROCHEMICAL SOC INC, 2014年, MOLTEN SALTS AND IONIC LIQUIDS 19, 64 (4), 45 - 56, 英語[査読有り]
研究論文(国際会議プロシーディングス)
A terahertz (THz) wire-grid polarizer is fabricated by imprinting porous Si followed by oblique evaporation of Ag. We demonstrate that it works in a wide frequency region covering from 5 to 18 THz with the extinction ratio of 10 dB. The frequency region is much wider than that of THz wire-grid polarizers fabricated by conventional imprint lithography using organic materials. The result suggests that imprinting of porous Si is a promising fabrication technique to realize low-cost wire-grid polarizers working in the THz region. © 2013 Optical Society of America.
2013年12月01日, Optics Letters, 38 (23), 5067 - 5070, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
[査読有り]
研究論文(国際会議プロシーディングス)
The stability constants of ML-type complexes of the two linear triphosphate ligand anion analogues triphosphate () and diimidotriphosphate () were investigated thermodynamically using potentiometric titrations according to Schwarzenbach's procedure. The stability constants of the ML-type complexes of different divalent metal ions with are larger than those of the corresponding complexes with because of the greater basicity of the imino group. The order of the stability constants for the ML-type complexes follows the Irving-Williams order, indicating that only non-bridging oxygen atoms are coordinated directly to the different metal ions in both ligands, and that the imino groups cannot participate in coordination to the metal ions. In the complexation reactions of the Ca2+, Sr2+, Ba2+- and Cu2+, Zn2+, Ni2+- systems, each metal ion forms an enthalpically stable complex, and there was no suggestion of a conspicuous entropic effect based on the chelate effect. Monodentate complexes that are strongly coordinated with the ligands were therefore formed, whereas entropically stable bidentate complexes were formed in the complexation reactions of the Cu2+, Zn2+, Ni2+- and Ca2+, Ba2+, Sr2+- systems. According to the HSAB concept, hard metal cations such as Ca2+, Ba2+ and Sr2+ should bind to the harder oxygen atoms rather than the softer nitrogen atoms of the imidopolyphosphate anions, preventing direct coordination to the imino nitrogen atom.
SPRINGER/PLENUM PUBLISHERS, 2013年11月, JOURNAL OF SOLUTION CHEMISTRY, 42 (11), 2104 - 2118, 英語[査読有り]
研究論文(学術雑誌)
[査読有り][招待有り]
研究論文(国際会議プロシーディングス)
The optimum coordination structure of Ni-fluoro complexes for the preparation of Ni-Al LDH by LPD process and the diverse anion-exchange properties of as-deposited Ni-Al on alpha-alumina powder were quantitatively evaluated for the industrial application of new positive material for alkali secondary batteries. The [NiF6-x-y(NH3)(x)(OH-)(y)](n+) was more suitable than [NiF6](4-) as the precursor of the deposition of Ni-Al LDH in the LPD reaction, and the improved LPD reaction achieved the synthesis of high purity and high crystallinity Ni-Al LDH. All anion-exchanged Ni-Al LDHs for OH--, Cl--, SO42-, and CH3COO--forms kept the high crystallinity and showed the enlargement of interlayer distances. The tilting angle of the intercalated CH3COO- anions was about 15 degrees. Anion-exchange capacity remained constant at a minimum of 0.8 meq g(-1) in pH >10, increased as pH decreased, and reached a maximum of 8 meq g(-1) at pH 2. Anion-exchange of OH--form of Ni-Al LDH was accelerated by the neutralization of hydroxide ions in interlayers, in addition, the anion-exchange capacity and the crystallinity of Ni-Al LDH could be controlled by the amount of doped aluminum ions. (C) 2013 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2013年08月, MATERIALS CHEMISTRY AND PHYSICS, 141 (1), 445 - 453, 英語[査読有り]
研究論文(学術雑誌)
A TiO2-dispersed Nafion (Nafion TiO2) membrane is prepared by the liquid phase deposition (LPD) method by carrying out a hydrolysis reaction of titanium fluoro complex in an aqueous solution. The conductivity of the TiO2-modified membrane is studied. The obtained composite membrane has dispersed TiO2 nanoparticles which enhance the membrane's hydrophilic and hygroscopic properties of polymer electrolyte fuel cells (PEFCs) under high temperature conditions. Change in the amount of TiO2 deposited on the Nafion membrane from 0.07 to 0.18 wt% for LPD reaction periods ranging from 3 to 9 h does not result in any change in the membrane's ion-exchange capacities. High resolution transmission electron microscopy (HRTEM) images indicate the growth and agglomeration of TiO2 particles at the surface during the LPD reaction. The diffusion of TiO2 is observed in the membrane from its surface up to a depth of ca. 20 mu m by means of XPS measurement. The water retention capacity of the membrane is improved from 63% to 83% at 200 degrees C by the deposition of 0.18 wt% of TiO2. Consequently, we find the small amount of TiO2 improved water management and increase the proton conductivity. (C) 2013 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2013年07月, JOURNAL OF POWER SOURCES, 233, 148 - 156, 英語[査読有り]
研究論文(学術雑誌)
We report the optimized preparation by liquid phase deposition (LPD) of nickelealuminum layered double hydroxide/carbon (NieAl LDH/C) composites as nickel-based cathode materials. We investigate the influence of the LDH content on the properties of the composites prepared with various total volumes of the reaction solution while the solution composition and the amount of
ELSEVIER, 2013年03月, Journal of Power Sources, 225, 215 - 220, 英語[査読有り]
研究論文(学術雑誌)
A facile, eco-friendly, room-temperature method for rapid one-pot synthesis of Au@Pd bimetallic nanoparticles exhibiting a core-shell morphology (similar to 60 nm) has been developed based on the successive reduction of Au(III) and Pd(II) precursors with tryptophan (Trp) in an aqueous environment. The unique supramolecular chemistry arising due to the hydrogen bonded indole group layer over the Au core seemed critical in the formation Pd shell. The core-shell morphology and surface analysis of the resulting Au@Pd nanoparticles were confirmed by aberration corrected scanning transmission electron microscopy followed by X-ray photoelectron spectroscopy. The formation of the core (Au) and shell (Pd) was also confirmed by Energy Dispersive X-Ray elemental scanning analysis. The resulting Au, Pd and Au@Pd nanoparticles were also analysed by UV-Vis spectroscopy, X-ray diffraction and Dynamic Light Scattering. Our results suggest a simple coordination mechanism where the pre-stabilized poly-Trp Au core serves as a template to facilitate the subsequent reduction of Pd(II) via active carboxyl groups. This study effectively demonstrates for the first time that core-shell nanoparticle synthesis (reduction and stabilization) can be effectively achieved by simple amino acids like Trp in an aqueous reaction mixture.
ROYAL SOC CHEMISTRY, 2013年, RSC ADVANCES, 3 (40), 18367 - 18372, 英語[査読有り]
研究論文(学術雑誌)
In this work, we investigated the combined effects of Al doping and surface modification on the fabrication of a core-shell type ZnO/ZnS nanowires (NWs) and its structural, electrical, and photoluminescence (PL) properties. A systematic investigation for different concentrations of Al doping followed by surface modification with different thicknesses of ZnS layer was performed. Significant changes in the nature of PL spectra and electronic conductivity are observed and insight discussions are present. Structural characterization on the core-shell NWs reveals the successful fabrication of Al doped highly single crystalline ZnO core and polycrystalline ZnS shell with both ZnO and ZnS are of hexagonal wurtzite structure. Compared with the bare undoped ZnO NWs, Al doped core-shell ZnO/ZnS NWs exhibit two orders of magnitude improvement in the electronic conductivity and fivefold enhancement in the UV PL intensity. The Al doped core-shell ZnO/ZnS NWs shows an efficient improvement in the UV PL intensity than the undoped core-shell ZnO NWs. The obtained improvement in the PL result is explained on the basis of interfacial transfer of photogenerated charge carriers and modification of defects. © 2013 AIP Publishing LLC.
2013年, Journal of Applied Physics, 114 (13), 英語[査読有り]
研究論文(学術雑誌)
The electrical, thermal and structural properties of composite electrolyte containing Ce0.9Gd0.1O1.95 (GDC) powder and (Li0.52Na0.48)(2)CO3 eutectics are investigated by AC impedance, differential thermal analysis and polarized Raman scattering spectroscopy. The system shows a dependence of the electrical conductivity upon the temperature. The transition point varies with the apparent average thickness of the liquid phase, while the activation energy, Delta E-a, remains constant at any distance from the solid phase. Higher electrical conductivity was obtained for the GDC/(Li0.52Na0.48)(2)CO3 composite than that for alpha-Al2O3/(Li0.52Na0.48)(2)CO3. Even in the N-2 or Air gas flow, the weight loss caused by decomposition of CO3-2 ion based on Lux-Flood equilibrium was rarely observed. The symmetric stretching mode of the polarized Raman spectra shows that carbonate ion maintains its D-3h symmetry in the presence of ceria. A constant value of the depolarization ratio of the nu(1)(A'(1)) mode with regard to the apparent average thickness confirms that the symmetry of carbonate ions in the molten state is not altered by the presence of ceria powder. It was more stable than that for the system containing alpha-Al2O3 as a reference sample. These findings contribute to the understanding of the properties of ceria-based carbonate electrolyte for intermediate temperature solid oxide fuel cells. Copyright (c) 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2012年12月, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 37 (24), 19407 - 19416, 英語[査読有り]
研究論文(学術雑誌)
TiO2-modified silica-based MCM-41 (Si-MCM-41) was prepared by liquid phase deposition (LPD) without a conventional fluorine scavenger such as H3BO3. TiO2 was deposited on Si-MCM-41 by LPD reactions for 1-48 h. Using Si-MCM-41, TiO2 was deposited on the inner surface of silica with etching phenomena. After the LPD reactions, Si species were detected in the reaction solution as a result of etching phenomena of silica. It was confirmed that Si-MCM-41 also acted as a fluorine scavenger by dissolving and forming hexafluorosilicate in aqueous hexafluorotitanate solution. The deposition behavior was greatly influenced by the volume of the reaction solution. The photocatalytic activity of the modified Si-MCM-41 was much higher than that of conventional catalysts such as TiO2:P25.
CHEMICAL SOC JAPAN, 2012年10月, CHEMISTRY LETTERS, 41 (10), 1262 - 1264, 英語[査読有り]
研究論文(学術雑誌)
\We developed novel supramolecular gelators with simple molecular structures that could harden a broad range of solvents: aqueous solutions of a wide pH range, organic solvents, edible oil, biodiesel, and ionic liquids at gelation concentrations of 0.1-2 wt %. The supramolecular gelators were composed of a long hydrophobic tail, amino acids and gluconic acid, which were prepared by liquid-phase synthesis. Among seven types of the gelators synthesized, the gelators containing L-Val, L-Leu, and L-Ile exhibited high gelation ability to various solvents. These gelators were soluble in aqueous and organic solvents, and also in ionic liquids at high temperature. The gelation of these solvents was thermally reversible. The microscopic observations (TEM, SEM, and CLSM) and small-angle X-ray scattering (SAXS) measurements suggested that the gelator molecules self-assembled to form entangled nanofibers in a large variety of solvents, resulting in the gelation of these solvents. Molecular mechanics and density functional theory (DFT) calculations indicated the possible molecular packing of the gelator in the nanofibers. Interestingly, the gelation of an ionic liquid by our gelator did not affect the ionic conductivity of the ionic liquid, which would provide an advantage to electrochemical applications.
AMER CHEMICAL SOC, 2012年06月, LANGMUIR, 28 (25), 9259 - 9266, 英語[査読有り]
研究論文(学術雑誌)
Several nondestructive and semidestructive analyses were used to discriminate colorless transparent polyethylene bags. Transparent plastic bags made from low-density and linear low-density polyethylene usually contain antiblocking agents to prevent sticking of the film, which makes it difficult to open the mouths of plastic bags. Inorganic antiblocking agents are uniformly dispersed in polyethylene films, so they are easily observed using optical microscopy. The particle size distributions of the antiblocking agents were compared by statistical tests. Particle composition was examined by elemental analysis using energy-dispersive X-ray spectrometry with a scanning electron microscope and by molecular vibration analysis using a sensitive microscopic Raman spectrometer. The compositions could be determined nondestructively on the basis of the results. These data reinforce the morphological discrimination. Morphological discrimination of the dispersed antiblocking agent powders, statistical comparison of particle size distributions, and compositional analysis of the antiblocking agents strengthen the ability to discriminate polyethylene films.
WILEY-BLACKWELL, 2012年05月, JOURNAL OF FORENSIC SCIENCES, 57 (3), 744 - 749, 英語[査読有り]
研究論文(学術雑誌)
We investigate the effect of annealing atmosphere on the optical properties of Bi doped zeolites by diffuse reflectance, steady state and time-resolved photoluminescence (PL), and PL excitation measurements. The results reveal that zeolites can be used as an excellent host material to stabilize multiple Bi centers (Bi3+, Bi2+, and Bi-related near-infrared (NIR) active centers) in the framework, which shows ultra-broadband emission from visible to NIR range. Annealing in N2 leads to the partial conversion of Bi3+ ions into Bi2+ and Bi-related NIR active centers. Our results demonstrate that the broadband NIR emission may be attributed to the electronic transition of Bi low valence state, rather than a higher valence state. © 2011 Elsevier B.V. All rights reserved.
2012年03月, Optical Materials, 34 (5), 821 - 825[査読有り]
研究論文(学術雑誌)
A co-doped ceria-carbonate (Ce0.8Sm0.2-xCaxO2-delta-Na2CO3) has been synthesized by a co-precipitation method. The detailed electrochemical characterizations (e.g. impedance spectra, polarization curve and IV curves) of this composite material are reported and discussed. The two phase nanocomposite electrolytes with carbonate coated on the co-doped ceria displays dual (H+/O2-) ion conduction at low temperature (300-600 degrees C) in solid oxide fuel cell. The observed remarkable temperature-dependent of conductivity is attributed to the softening/melting of carbonate phase as the physical state of carbonate phase transforms from solid to molten state. Coexistence of various charge carriers, oxide phase composition, and the oxide-carbonate interfacial area are investigated by Raman spectra. The enhancement of conductivity is also discussed by the general mixing rule/percolation theory of composite interfaces. The co-doping with 2nd phase gives a good approach to realize challenges for solid oxide fuel cell. (C) 2011 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2012年03月, JOURNAL OF POWER SOURCES, 201, 121 - 127, 英語[査読有り]
研究論文(学術雑誌)
Zhenhua Bai, Minoru Fujii, Yuki Mori, Yuji Miwa, Minoru Mizuhata, Hong-Tao Sun, Shinji Hayashi, 2011, 'Efficient near-infrared luminescence and energy transfer in Nd-Bi codoped zeolites', <i>MRS Proceedings</i>, vol. 1342
2012年, Materials Research Society Symposium Proceedings, 1342, 61 - 66[査読有り]
研究論文(国際会議プロシーディングス)
Preparation method of silver nanoparticles (AgNPs) dispersed in Nafion 115 membrane using UV photoreduction process was established. The loading amount of AgNPs was controlled with UV irradiation time. AgNPs might exist in ionic cluster channel in Nafion membrane stably without any stabilizing reagent. The particle size was measured by transmission electron microscope (TEM). The mean particle size was ca. 13 nm in diameter. The obtained nanocomposite membrane has absorption bands due to local surface plasmon resonance (LSPR) at around 400 nm. The band position depends on the refractive index of suspension as expected by Mie theory. Furthermore very little amount of solvent affected the LSPR bands sensitively due to changing the highly localized refractive index.
ELECTROCHEMICAL SOC INC, 2012年, NANOTECHNOLOGY (GENERAL) - 220TH ECS MEETING, 30 (30), 9 - 18, 英語[査読有り]
研究論文(国際会議プロシーディングス)
[査読有り]
研究論文(国際会議プロシーディングス)
Ultraviolet-blue to near-infrared (NIR) downconversion is investigated for the Dy3+-Yb3+ couple in zeolites by steady-state and time-resolved photoluminescence (PL) spectra, and PL excitation spectra. Upon excitation of the 4F9/2 level of Dy3+, NIR quantum cutting could occur through a two-step energy transfer from one Dy 3+ ion to two neighbouring Yb3+ ions via an intermediate level. The energy transfer efficiency from the 4F9/2 level is estimated to be 42%, and the intrinsic PL quantum efficiency of Yb 3+ emission reaches 54%. The findings may have potential application in enhancing the energy efficiency of silicon-based solar cells. © 2011 IOP Publishing Ltd.
2011年11月16日, Journal of Physics D: Applied Physics, 44 (45), 1 - 5[査読有り]
研究論文(学術雑誌)
A series of Bi doped zeolites are prepared by an ion-exchange process by changing doping concentration in a wide range, and the optical properties are investigated. The near-infrared photoluminescence (PL) intensity, full width at half maximum and decay time depend strongly on Bi doping concentration. The PL intensity increases 178 times when the concentration is changed from 0.3 to 1.5 at. %. At the same time, the lifetime increases from 83 to 527 μs. The results prove the model that doped Bi acts not only as optically active centers, but also as pore-sealing substances to isolate the centers. The comparison of PL and Raman data suggests that in addition to previously proposed Bi 2O3, other Bi-related materials, probably Bi metal, play an important role to isolate the active centers. © 2011 Elsevier Inc. All rights reserved.
2011年11月, Microporous and Mesoporous Materials, 145 (1-3), 21 - 25[査読有り]
研究論文(学術雑誌)
Yb-Bi co-doped zeolites are prepared by a method consisting of a simple ion-exchange process and subsequent high-temperature annealing. We observe two strong near-infrared (NIR) emission bands overlapping in the range 930-1480 nm, corresponding to the electronic transitions of bismuth-related active centres (BiRAC) and Yb3+ ions, respectively. In the obtained products, the excitation wavelength of Yb3+ is extended to the range 420-850 nm, and the lifetime reaches 665 μs. In the zeolite matrix, Bi ions exist as BiRAC and Bi compound agglomerates. The former act as a sensitizer of Yb 3+ ions, and the latter act as a blockage to seal the pores of zeolites, which enables Yb3+ ions to show efficient NIR emission even if the zeolites contain a large amount of coordinated water. The excellent optical and structural properties make these NIR-emitting nanoparticles promising in applications as biological probes. © 2011 IOP Publishing Ltd.
2011年04月, Journal of Physics D: Applied Physics, 44 (15), 1 - 5[査読有り]
研究論文(学術雑誌)
Nd-Bi codoped zeolites were prepared by an ion-exchange process, and the optical properties were investigated by photoluminescence (PL) and PL excitation spectra, and decay time measurements. The results show that the NIR emission of Nd3+ ions is significantly enhanced by the introduction of bismuth in codoped samples, and the lifetime reaches 246 μs. It is also observed that NIR-active Bi acts as a sensitizer of Nd3+ ions. The energy transfer efficiency is also estimated. The peculiar optical properties make Nd-Bi codoped zeolites promising for potential application in biological probes. © 2011 Optical Society of America.
2011年03月15日, Optics Letters, 36 (6), 1017 - 1019[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
Nickel-aluminum layered double hydroxide/carbon (Ni-Al LDH/C) composites have been fabricated using a mixed solution of {Al(NO3)(3)center dot 9H(2)O and H3BO3} as fluoride scavengers in the liquid phase deposition (LPD) process. The amount of divalent Ni2+ substituted by trivalent Al3+ within the lattice of alpha-Ni(OH)(2) was controlled by the concentration of Al(NO3)(3)center dot 9H(2)O solution. X-ray diffraction studies reveal pure phase Ni-Al LDH, isostructural and isomorphic to alpha-Ni(OH)(2) with higher interlayer distance. The electrochemical properties of the cathode materials containing 0, 8.6, 13.8, 17.8, 21.3 and 23.4 Al% were evaluated by the means of charge-discharge and cyclic voltammetry measurements. The overall comparison indicates that Ni-Al LDH/C composites have higher electrochemical performance than pure alpha-Ni(OH)(2)/C composite. The cathode with 17.8 Al% exhibits the best performance at 1 C compared to other Al3+ contents: a much lower voltage plateau, well separated from the oxygen evolution at the end of the charging as well as a single flat and high discharge plateau with a discharge capacity of 376.9 mAh g(comp)(-1). Short term durability test for 80 cycles showed that the electrode containing 13.8 Al% has the highest discharge rate at 2 C. The range of Al substitution 13.8-17.8 Al% provides a good electrochemical response. (C) 2010 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2010年11月, JOURNAL OF POWER SOURCES, 195 (22), 7669 - 7676, 英語[査読有り]
研究論文(学術雑誌)
High purity and well crystallized tungsten acid hydrates (H2WO4 center dot H2O) thin films were prepared from H2WO4-HF(aq.) and H3BO3 as precursors by the liquid phase deposition method. The crystal structure was indexed as monoclinic with unit cell lattice constants a = 7.517 angstrom, b = 6.907 angstrom, c = 3.694 angstrom and beta = 89.58 degrees. The monoclinic phase was transformed into orthorhombic WO3 center dot H2O after heating at 100 C. Further heating from 300 to 500 degrees C resulted in an anhydrous monoclinic WO3 films. The effects of the composition and the reaction time on the deposition and the microstructures of the deposited films were studied by the means of scanning electron microscope (SEM), transmission electron microscope (TEM). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The film formation showed strong dependence upon the composition, whereas the amount of deposition, the shape and the films thickness could be controlled by the reaction time. Cross-sectional TEM image of WO3 film deposited on Au wire indicated that the epitaxial growth of the film was maintained after calcination at 500 degrees C. XPS analysis also revealed the existence of W6+ ions in both the deposited and calcined films. (C) 2010 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2010年10月, MATERIALS CHEMISTRY AND PHYSICS, 123 (2-3), 614 - 619, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
With a view to developing an economical and elegant biosensor chip, we compared the efficiencies of biosensors that use gold-coated single-crystal silicon and amorphous glass substrates. The reflectivity of light over a wide range of wavelengths was higher from gold layer coated single-crystal silicon substrates than from glass substrates. Furthermore, the efficiency of reflection from gold layers of two different thicknesses was examined. The thicker gold layer (100 nm) on the single-crystal silicon showed a higher reflectivity than the thinner gold film (10 nm). The formation of a nucleic acid duplex and aptamer-ligand interactions were evaluated on these gold layers, and a crystalline silicon substrate coated with the 100-nm-thick gold layer is proposed as an alternative substrate for studies of interactions of biomolecules.
SPRINGER HEIDELBERG, 2010年09月, ANALYTICAL AND BIOANALYTICAL CHEMISTRY, 398 (2), 751 - 758, 英語[査読有り]
研究論文(学術雑誌)
We have shown that tunable and highly efficient broadband near-IR (NIR) luminescence can be realized in erbium/bismuth codoped zeolites. The emission covers the ranges of 930-1450 nm and 1450-1630 nm. The intensity ratio of the two bands can be tuned by adjusting the concentration of erbium and the excitation wavelength. Steady-state and time-resolved photoluminescence (PL), and PL excitation measurements indicate that two kinds of emitters coexist in the pores of zeolites, and that NIR active bismuth simultaneously acts as a sensitizer of erbium. The present results demonstrate an important rational strategy for the design of a tunable NIR-emitting zeolite-based na-nosystem. © 2010 Optical Society of America.
2010年06月01日, Optics Letters, 35 (11), 1926 - 1928[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
The anionic binary Ionic liquids; TMPAFSA(x)TFSA(1-x) were prepared as mixture of TMPATFSA and TMPAFSA. From the results of DSC analysis, the binary system showed the simple binary eutectic phase diagram and the eutectic point was found at the composition point of x = 0.33. In this system, each anion vibrated independently and showed isomerization equilibria displacement with temperature change. It was suggested that the equilibria displacements affected to the liquid structure and cis-trans isomerization of each anion played an important role in the solidification of TMPAFSA(x)TFSA(1-x).
ELECTROCHEMICAL SOC INC, 2010年, PHYSICAL AND ANALYTICAL ELECTROCHEMISTRY IN IONIC LIQUIDS, 25 (39), 3 - 12, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The electrical, thermal and structural properties of CeO2/(Li0.52Na0.48)(2)CO3 coexisting system are investigated by AC impedance, differential thermal analysis and polarized Raman scattering spectroscopy. The system shows a dependence of the electrical conductivity upon the temperature. The transition point varies with the apparent average thickness of the liquid phase, while the activation energy, Delta E-a, remains constant at any distance from the solid phase. The symmetric stretching mode of the polarized Raman spectra shows that carbonate ion maintains its D-3h symmetry in the presence of ceria. A constant value of the depolarization ratio of the v(1)(A'(1)) mode with regard to the apparent average thickness confirms that the symmetry of carbonate ions in the molten state is not altered by the presence of ceria powder. These findings contribute to the understanding of the properties of ceria-based carbonate electrolyte for intermediate temperature fuel cells.
ELECTROCHEMICAL SOC INC, 2010年, MOLTEN SALTS AND IONIC LIQUIDS 17, 33 (7), 439 - 447, 英語[査読有り]
研究論文(国際会議プロシーディングス)
We report on highly efficient broadband near-infrared photoluminescence (PL) in Ni2+-doped glass ceramics (GCs) films fabricated by annealing Si/Ni2+-doped glass superlattices (SNGS). Over two orders of magnitude enhancement of PL can be achieved in comparison with that from the annealed glass film. The PL lifetime of the annealed SNGS is several milliseconds, which is much longer than those of bulk GCs. The strong PL enhancement results from the formation of high-quality cordierite nanocrystals because the Si layers act as Si source for the crystal growth. This technique can be extended to fabricate other types of high-quality GCs films. © 2009 Elsevier B.V. All rights reserved.
2009年11月15日, Journal of Non-Crystalline Solids, 355 (48-49), 2425 - 2428[査読有り]
研究論文(学術雑誌)
Erbium silicate (Er 2SiO 5 and Er 4Si 3O 12) nanostructures were successfully synthesized by a facile molten-salt approach in the presence of NaCI and surfactant. The synthesized products were structurally and morphologically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM), whereas the luminescent properties were characterized by temperaturedependent luminescence measurements. The results revealed that the composition, crystalline phase, and yield of the final products can be readily controlled by choosing suitable surfactant and tailoring the molar ratio of reactants used for the reactions. Moreover, the single-crystalline nature of Er 2SiO 5 and of Er 4Si 3O 12 nanostructures results in sharp photoluminescence (PL) of Er 3+, and both nanostructures are immunized from temperature quenching of PL. We suggest that the nanostructures developed in the present work are promising building blocks for Si-based optoelectronics nanodevices. Copyright © 2009 American Scientific Publishers.
2009年11月, Journal of Nanoscience and Nanotechnology, 9 (11), 6277 - 6282[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
We have successfully tailored a soft solution process for the synthesis of monodispersed SnO2 nanoparticles, applying a liquid phase deposition technique from an aqueous reaction mixture without any post-annealing treatment. The synthesis was carried out by varying poly(ethylene glycol) (PEG) content in the reaction mixture. The XRD patterns of the nanoparticles exhibited the formation of SnO2 cassiterite phase, irrespective of the PEG content in the composition of the reaction solution, the reaction time, and the reaction temperature. The mean size and the standard deviation of SnO2 nanoparticles exhibited a decreasing trend with increasing PEG concentration.
CHEMICAL SOC JAPAN, 2009年10月, CHEMISTRY LETTERS, 38 (10), 974 - 975, 英語[査読有り]
研究論文(学術雑誌)
Hexagonal molybdenum trioxide thin films with good crystallinity and high purity have been fabricated by the liquid phase deposition (LPD) technique using molybdic acid (H(2)MoO(4)) dissolved in 2.82% hydrofluoric acid (HF) and H(3)BO(3) as precursors. The crystal was found to belong to a hexagonal hydrate system MoO(3)center dot nH(2)O (n similar to 0.56). The unit cell lattice parameters are a = 10.651 angstrom, c = 3.725 angstrom and V = 365.997 angstrom(3). Scanning electron microscope (SEM) images of the as-deposited samples showed well-shaped hexagonal rods nuclei that grew and where the amount increased with increase in reaction time. X-ray photon electron spectroscopy (XPS) spectra showed a Gaussian shape of the doublet of Mo 3d core level, indicating the presence of Mo(6+) oxidation state in the deposited films. The deposited films exhibited an electrochromic behavior by lithium intercalation and deintercalation, which resulted in coloration and bleaching of the film. Upon dehydration at about 450 degrees C, the hexagonal MoO(3)center dot nH(2)O was transformed into the thermodynamically stable orthorhombic phase. (C) 2009 Elsevier Inc. All rights reserved.
ACADEMIC PRESS INC ELSEVIER SCIENCE, 2009年09月, JOURNAL OF SOLID STATE CHEMISTRY, 182 (9), 2362 - 2367, 英語[査読有り]
研究論文(学術雑誌)
Raman spectra and the polarization behaviors of molten alkali carbonates coexisting inorganic powder were measured. The deformation and the change of polarization properties by the coexisting with the solid phase are discussed. The symmetry of the band shape of the Raman spectra for CO32- stretching band (v(1)) was deformed asymmetrically by coexisting with alpha-Al2O3 powder. The deconvolution of spectra of mixtures exhibited two band components. The observed bands are evidence of the existence of two different types of CO32- ions in these systems. Raman depolarization ratio for molten carbonate systems increases from the base line with the decrease of the apparent average thickness. The degree of the anomalous behavior of the molten carbonate by the solid phase have been observed in the order of alpha-Al2O3 > gamma-LiAlO2 > ZrO2 Which is related to the surface acidity defined by the value of point of zero charge (pzc). Consequently, the carbonate ion is deformed asymmetrically by coexisting with inorganic oxide powder.
ELECTROCHEMICAL SOC JAPAN, 2009年08月, ELECTROCHEMISTRY, 77 (8), 721 - 724, 英語[査読有り]
研究論文(学術雑誌)
The effects of secondary cationic species on the ordering structure in room temperature ionic liquids (RTILs) are discussed. Binary RTILs refer to mixture of trimetyl-n-octylammonium bis(trifluoromethanesulfonyl)imide (N-1118[TFSA]) and alkali or alkali-earth metal bis(trifluoromethanesulfonyl)imide (M[TFSA](y); M = Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba) in an appropriate molar ratio (x = 0.1, 0.2, 0.3, 0.5), denoted as M-x[N-1118](1-x)[TFSA](1-x+xy). From SAXS and WAXS measurements of M-x[N-1118](1-x)[TFSA](1-x+xy), the intensity of First peak derived from the ordering structure increases with addition of M[TFSA](y). It is suggested that the metal cation has an intensive interaction with TFSA anion and cationic structural ordering are enhanced. We discussed the relationship between ionic size and the formation mechanism of the local ordering structure in binary ionic liquids containing alkali metal and alkali earth metal based on aliphatic quaternary ammonium (AQA) cations is clarified.
ELECTROCHEMICAL SOC JAPAN, 2009年08月, ELECTROCHEMISTRY, 77 (8), 725 - 729, 英語[査読有り]
研究論文(学術雑誌)
Nickel-doped forsterite (Ni2+:Mg2SiO4) nanocrystals have been synthesized by a facile molten-salt approach in the presence of NaCl and a surfactant (NP-7.5). The products were characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction (SAED), and luminescence spectra measurements. The crystal size could be controlled by tailoring the synthesis parameters. TEM, high-resolution TEM, and SAED results revealed the single crystalline character of Mg2SiO4 nanoparticles. A possible model for the growth of Ni2+:Mg2SiO4 nanocrystals was postulated. The obtained Ni2+:Mg2SiO 4 nanocrystals show strong, super broad, near-infrared luminescence at room temperature. These doped Mg2SiO4 nanocrystals are promising gain mediums for super broadband optical amplification. © 2009 The American Ceramic Society.
2009年04月, Journal of the American Ceramic Society, 92 (4), 962 - 966, 英語[査読有り]
研究論文(学術雑誌)
We have shown that efficient superbroadband near-IR luminescence can be realized in bismuth-doped high- silica nanocrystalline zeolites. The emission band covered the range of 930-1620 nm, with a maximum peak at 1146.3 nm, an FWHM of 152 nm, and a lifetime of over 300 μs under the excitation of a 488 nm laser line. The observed luminescence was attributed to subvalent Bi (Bi +) ions formed in the annealed zeolites. These Bi-doped nanozeolites may find applications as superbroadband near-IR nano-optical sources. © 2009 Optical Society of America.
2009年04月, Optics Letters, 34 (8), 1219 - 1221[査読有り]
研究論文(学術雑誌)
Significantly enhanced superbroadband near infrared emission has been realized in bismuth/aluminum doped high-silica zeolite derived nanoparticles. The emission intensity can be easily tailored by the introduction of aluminum. The luminescence lifetime can reach up to 695 ìs. The results reveal that the existence of charge imbalance environment caused by [AlO4/2]- units in host materials is requisite to the formation of infrared-active Bi+. The finding presents a feasible route to design highefficient bismuth activated infrared luminescent nanoparticles. These bismuth doped nanoparticles may find applications as superbroadband near infrared nano optical sources. © 2009 Optical Society of America.
2009年04月, Optics Express, 17 (8), 6239 - 6244, 英語[査読有り]
研究論文(学術雑誌)
Nickel-doped forsterite (Ni2+:Mg2SiO4) nanocrystals have been synthesized by a facile molten-salt approach in the presence of NaCl and a surfactant (NP-7.5). The products were characterized by X-ray diffraction, transmission electron microscopy (TEM), high-resolution TEM, selected area electron diffraction (SAED), and luminescence spectra measurements. The crystal size could be controlled by tailoring the synthesis parameters. TEM, high-resolution TEM, and SAED results revealed the single crystalline character of Mg2SiO4 nanoparticles. A possible model for the growth of Ni2+:Mg2SiO4 nanocrystals was postulated. The obtained Ni2+:Mg2SiO 4 nanocrystals show strong, super broad, near-infrared luminescence at room temperature. These doped Mg2SiO4 nanocrystals are promising gain mediums for super broadband optical amplification. © 2009 The American Ceramic Society.
2009年04月, Journal of the American Ceramic Society, 92 (4), 962 - 966[査読有り]
研究論文(学術雑誌)
High purity alpha-nickel hydroxide/carbon composite has been synthesized by the liquid phase deposition (LPD) method. The purity of the as-prepared samples was confirmed by X-ray photon electron (XPS) survey spectra, which showed no other peak than that of the core levels Ni 2p, O 1s, C1s, Ni 3s and Ni 3p involved in the process. Scanning electron microscope (SEM) images showed carbon particles randomly embedded within the Ni(OH)(2) network. The amount of deposited nickel hydroxide can be controlled by the ratio between carbon and the quantity of the treatment solution, and the reaction time. (C) 2009 The Ceramic Society of Japan. All rights reserved.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2009年03月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 117 (1363), 392 - 394, 英語[査読有り]
研究論文(学術雑誌)
Organic compound/metal oxide composite thin films have been prepared by the liquid-phase deposition method in a one-step deposition technique. Organic dyes were added to the metal fluoro-complexes aqueous solution in order to entrap these dyes within the growing thin films of metal oxides, yielding organic dye/metal oxide hybrid materials. According to Raman spectroscopy and X-ray photoelectron spectroscopy, the formation of the materials in the case of cationic dyes can be explained by the electrostatic interaction between negative charge density at the fluorinated surface of metal oxides and the cationic dyes. UV-Vis results indicate that stilbazo and pyrocatechol violet (catecholate dye molecules) form a charge transfer complex with metal oxides through the catechol moiety with a bidentate linkage. (C) 2009 The Ceramic Society of Japan. All rights reserved.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2009年03月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 117 (1363), 326 - 329, 英語[査読有り]
研究論文(学術雑誌)
The equilibrium reaction of H2SiF6 Solution in the LPD method was investigated by the measurement of UV and IR spectroscopies, vapor pressure and electric conductivity. These measurements were carried out by adding the F- scavenger such as H3BO3 and Al metal which shifts the equilibrium reaction. The experimental results strongly suggested the presence of SiF4 and [SiF6 center dot SiF4](2-) in H2SiF6 solution. These species were estimated to be involved in the LPD process as intermediates and important for controlling the deposition process of metal oxide. (C)2009 The Ceramic Society of Japan. All rights reserved.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2009年03月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 117 (1363), 335 - 339, 英語[査読有り]
研究論文(学術雑誌)
Er3+ and Ni2+ doped single-crystalline Al 18B4O33 nanorods were synthesized by a facile one-step toxic-free combustion method. The products were characterized by x-ray diffraction, transmission electron microscopy, selected area electron diffraction, and integrated and time-resolved photoluminescence (PL) measurements. The phase purity, morphology, and PL properties of Er3+ and Ni2+ doped Al18B4O33 nanorods can be readily controlled by tailoring the annealing temperature. The mechanism for the formation of Al18B4O33 nanorods with different aspect ratio is discussed. Er3+ doped Al18B 4O33 nanorods show strong PL centered at 1531 nm, while Ni2+ doped products show superwide PL with a full width at half maximum of up to 250 nm. These aluminum borate nanostructures are promising building blocks for optoelectronics nanodevices. © IOP Publishing Ltd.
2009年01月21日, Nanotechnology, 20 (3), 英語[査読有り]
研究論文(学術雑誌)
Er3+ and Ni2+ doped single-crystalline Al 18B4O33 nanorods were synthesized by a facile one-step toxic-free combustion method. The products were characterized by x-ray diffraction, transmission electron microscopy, selected area electron diffraction, and integrated and time-resolved photoluminescence (PL) measurements. The phase purity, morphology, and PL properties of Er3+ and Ni2+ doped Al18B4O33 nanorods can be readily controlled by tailoring the annealing temperature. The mechanism for the formation of Al18B4O33 nanorods with different aspect ratio is discussed. Er3+ doped Al18B 4O33 nanorods show strong PL centered at 1531 nm, while Ni2+ doped products show superwide PL with a full width at half maximum of up to 250 nm. These aluminum borate nanostructures are promising building blocks for optoelectronics nanodevices. © IOP Publishing Ltd.
2009年01月21日, Nanotechnology, 20 (3)[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(学術雑誌)
Hong-Tao Sun, Akinobu Hosokawa, Yuji Miwa, Fumiaki Shimaoka, Minoru Fujii, Minoru Mizuhata, Shinji Hayashi, Shigehito Deki, 2009, 'ChemInform Abstract: Strong Ultra-Broadband Near-Infrared Photoluminescence from Bismuth-Embedded Zeolites and Their Derivatives.', <i>ChemInform</i>, vol. 40, no. 47
2009年, ChemInform, 40 (47)[査読有り]
Organic compound/metal oxide composite thin films have been prepared by the liquid-phase deposition method in one-step deposition technique. Organic dyes were added to the metal fluoro-complexes aqueous solution in order to entrap these dyes within the growing thin films of metal oxides, yielding organic dye/metal oxide hybrid materials. According to Raman spectroscopy and X-ray photoelectron spectroscopy, the formation of the materials in the case of cationic dyes can be explained by electrostatic interaction between negative charge density at the fluorinated surface of metal oxides and the cationic dyes. UV-Vis results indicate that stilbazo and pyrocatechol violet (catecholate dye molecules) form a charge transfer complex with metal oxides through the catechol moiety with a bidentate linkage. ©The Electrochemical Society.
2009年, ECS Transactions, 16 (25), 73 - 83, 英語[査読有り]
研究論文(国際会議プロシーディングス)
We have shown that highly efficient and air-stable 1531 nm emission can be realized in erbium/bismuth codoped zeolites. The luminescence lifetime of Er3+ at 1531 nm can reach up to 4.2 ms. Bismuth compounds formed by high temperature annealing can act as blockages of selectively closing down the "in-out windows" of water molecules, i.e., Er3+ ions are sealed in a low-vibrational environment by bismuth agglomerates even when the samples contain a large amount of water. This finding may pave the way for the applications of active ions doped porous materials in infrared photonics. © 2009 American Institute of Physics.
2009年, Applied Physics Letters, 94 (14), 141106[査読有り]
研究論文(学術雑誌)
Zeolites with embedded bismuth compounds display strong, air-stable, long-lived, ultrabroadband, and tunable near-infrared photoluminescence (see picture). Bismuth ions not only act as luminescence-active centers, but also as blocks for selectively closing the "in-out windows" of water molecules. Bismuth active centers can be sealed in a low-vibrational environment by bismuth agglomerates even when the sample still contains a large amount ofwater. © 2009 WILEY-VCH Verlag GmbH & Co. KGaA.
2009年, Advanced Materials, 21 (36), 3694 - 3698[査読有り]
研究論文(学術雑誌)
The effects of fluoride ions scavenger in the liquid phase deposition synthesis of nickel-aluminum layered double hydroxide/carbon (Ni-Al LDH/C) composite have been investigated. Al(NO3)3.9H 2O, AlCl3, Al metal plate, and a mixed solution of [Al(NO3)3.9H2O and H3BO3] were employed as F- scavengers. In the case that Al material is solely used as F-scavenger, α-nickel hydroxide is the predominant phase, and a small amount of β-phase is detected. In contrast pure phase Ni-Al LDH/C composites, isostructural and isomorphic to α-Ni(OH)2 are obtained when a mixed solution of Al(NO3)3.9H 2O and H3BO3 is used at any range of Al content. High purity LDHs without cationic species exhibited good stability in 6M KOH for 7 days. Short-term charge-discharge measurements at 1C-rate for the electrodes containing 0, 13.6 and 17.8 Al mol % showed an increase of the discharge capacity with increasing Al content. ©The Electrochemical Society.
2009年, ECS Transactions, 19 (27), 41 - 46, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Large-scale synthesis of ytterbium silicate (Yb2SiO5) nanoparticles and nanorods has been realized by a facile molten-salt approach. The synthesized products were structurally and morphologically characterized by X-ray diffraction, transmission electron microscopy (TEM), and high-resolution TEM. Our results revealed that the morphologies of Yb2SiO5 products can be readily controlled by a simple variation of the reactants used for the molten-salt reaction. Single-crystalline Yb2SiO5 nanorods with a high yield can be obtained using NP-7.5 as a surfactant. The formation mechanism of Yb2SiO5 nanostructures was also discussed. The method presented here for the synthesis of Yb2SiO 5 nanostructures may pave the way for their application as environmental barrier coating materials. © 2008 The American Ceramic Society.
2008年12月, Journal of the American Ceramic Society, 91 (12), 4158 - 4161[査読有り]
研究論文(学術雑誌)
研究論文(国際会議プロシーディングス)
We designed and fabricated porous silicon-based broadband rugate filters by combining up to five rugate structures. A near-infrared stop-band filter having a reflection band width of 1356 nm with no higher-order harmonics and very small sidelobes were realized. The suppression of higher-order harmonics and the reduction of sidelobes also allowed us to produce a high quality pass-band filter exhibiting a high transmittance region sandwiched by two broad stop-bands. © 2008 Elsevier B.V. All rights reserved.
2008年09月, Optical Materials, 31 (1), 102 - 105[査読有り]
研究論文(学術雑誌)
The liquid phase deposition (LPD) of metal oxide thin films at the liquid-liquid interface was investigated. Just after the start of the LPD reaction, depositions were observed continually at the liquid-liquid interface. The deposition grew two-dimensionally into a self-standing film with thickness of 1 mu m and domain size of up to ca. 1 mm without any solid substrates. The self-standing film was formed with asymmetrical morphology, which consisted of flat surface on the side of the liquid-liquid interface and relatively rough surface on the side of the bulk solution. The structure was characterized by Raman spectroscopy, confirming that metastable ammonium titanium oxide fluoride (NR4TiOF3) was first deposited at the liquid-liquid interface, on which anatase-type titanium oxide (TiO2) was deposited second to forming the asymmetrical bilayer structure. It was suggested that the metal fluoride complex of the precursor was concentrated in the vicinity of the liquid-liquid interface compared with the solid-liquid interface due to the difference of the interfacial free energy, which could cause formation of the asymmetrical structure. The liquid-liquid interface could be confirmed as the specific reaction field for the LPD reaction. Also, the other metal oxide self-standing films such as tin oxide (SnO2) and iron hydroxide oxide (beta-FeOOH) were obtained in this process. The process also has great potential not only for basic science but also in the engineering field such as a soft solution process for template-free synthesis.
AMER CHEMICAL SOC, 2008年09月, JOURNAL OF PHYSICAL CHEMISTRY C, 112 (35), 13535 - 13539, 英語[査読有り]
研究論文(学術雑誌)
Deep reactive ion etching (Deep-RIE) process was established for fabrication of highly nano-ordered metal oxide thin films such as TiO2, ZrO2, SnO2 etc, by the liquid phase infiltration (LPI) method. Electron beam lithography (EBL) technique and Deep-RIE were adapted to fabricate the Si wafer coated with a positive resist ZEP520A. Etching gas of SF6 and C4F8 was used for Deep-RIE process. The flow rate and repeating time were optimized in order to obtain the straight shape on the sidewalls of the trench or pillar structure. We used polymethylmethacrylate (PMMA) and acetylcellulose as a replica films. The transcribed replica films are applied to the liquid phase deposition reaction. The film structure was completely reproduced from the original shape of the designed Si wafer. The optical interference on the fabricated metal oxide thin films was also observed using absolute reflective visible spectroscopy. (c) 2007 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2008年02月, MICROELECTRONIC ENGINEERING, 85 (2), 355 - 364, 英語[査読有り]
研究論文(学術雑誌)
We designed and fabricated porous silicon-based broadband rugate filters by combining up to seven rugate structures. A near-infrared stop-band filter having a reflection band width of 1926 nm with no higher-order harmonics and very small sidelobes were realized. The suppression of higher-order harmonics and the reduction of sidelobes also allowed us to produce a high quality pass-band filter having three high transmittance regions consisting of broad stopbands. © The Electrochemical Society.
2008年, ECS Transactions, 16 (3), 55 - 59, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The effects of hetero-species on the local ordering structure composed of AQA cation are discussed with alkali metal- and alkali earth metal cations (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, and Ba2+) as hetero-species, taking into account the difference of ionic potential of metal cations. The effects of secondary cationic species on the ordering structure in ILs are discussed. Binary ILs refer to mixture of N111,8[TFSI] and M[TFSI] 2 (M = Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+) in an appropriate molar ratio (x = 0.1, 0.2, 0.3, 0.5, z=1, 2), denoted as MxN111,81-x[TFSI] {1+(z-1)x}. From the results of SAXS and WAXS measurement of M xN111,81-x[TFSI]{(1+(z-1)x}, the intensity assigned to ordering structure increases with addition of M[TFSI]z and, is higher in mixed with alkali earth metal cation than alkali metal cation. Cationic structural ordering is enhanced by the effects of added metal cation. ©The Electrochemical Society.
2008年, ECS Transactions, 16 (49), 69 - 77, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The equilibrium reaction of fluorosilicate ion (SiF6 2-) in the LPD method was investigated by the measurement of UV and IR spectroscopies, Raman spectroscopy. These measurements were carried out by adding the F- scavenger such as H3BO3 and Al metal which shifts the equilibrium reaction. Also, the concentration of Si dissolving species was measured after addition of fine α-Al2O3 powder. These species were estimated to be involved in the LPD process as intermediates and important for controlling the deposition process of metal oxide. ©The Electrochemical Society.
2008年, ECS Transactions, 16 (46), 93 - 101, 英語[査読有り]
研究論文(国際会議プロシーディングス)
SnO2 thin film was prepared from a SnF2-HF aqueous solution with the addition of H3BO3 aqueous solution by the Liquid Phase Deposition (LPD) method. We focused on the construction of the continuous deposition system and the control of the deposition rate. Parent solution containing SnF2-HF was intermittently added to the treatment solution, which consists of the excess amount of H3BO3. As a result, the deposition rate can be maintained almost constant, at least for 24 h, and uniform SnO2 film with the thickness of more than 600 nm was obtained.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2007年12月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 115 (1348), 856 - 860, 英語[査読有り]
研究論文(学術雑誌)
Composite materials with europium (III) ion-doped zirconia (ZrO2:Eu3+) infiltrated SnO2 inverse opal have been prepared by the liquid phase infiltration (LPI) process. The absolute reflectance spectra measurement for ZrO2:Eu3+ infiltrated SnO2 inverse opal showed photonic stop band due to three-dimensionally (3D) ordered structure. Photonic stop band of ZrO2:Eu3+ infiltrated SnO2 inverse opals was shifted to longer wavelength compared with SnO2 inverse opals due to the increase of average refractive index. The ZrO2:Eu3+ infiltrated SnO2 inverse opal showed stronger emission intensity than ZrO2:Eu3+ thin film without 3D ordered structure.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2007年11月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 115 (1347), 724 - 728, 英語[査読有り]
研究論文(学術雑誌)
Composite materials with europium (III) ion-doped zirconia (ZrO2:Eu3+) infiltrated SnO2 inverse opal have been prepared by the liquid phase infiltration (LPI) process. The absolute reflectance spectra measurement for ZrO2:Eu3+ infiltrated SnO2 inverse opal showed photonic stop band due to three-dimensionally (3D) ordered structure. Photonic stop band of ZrO2:Eu3+ infiltrated SnO2 inverse opals was shifted to longer wavelength compared with SnO2 inverse opals due to the increase of average refractive index. The ZrO2:Eu3+ infiltrated SnO2 inverse opal showed stronger emission intensity than ZrO2:Eu3+ thin film without 3D ordered structure.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2007年11月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 115 (1347), 724 - 728, 英語[査読有り]
研究論文(学術雑誌)
The electrical conductivity of alkali molten carbonates coexisting with gamma-LiAlO2 powders have been measured by ac impedance method. The temperature and composition dependence of the electrical conductivity are investigated. The effects of the solid phase upon the ionic species are discussed. The electrical conductivity varies with the liquid content and drastically increases at ca. 30 vol.%. The Arrhenius plot shows an increase of the electrical conductivity with increasing temperature. A significant value of the electrical conductivity below the salt melting point is observed. This indicates the existence of a non-frozen phase assuming conduction within the system. The activation energy increases with a decrease of apparent average thickness of the liquid layer. The influence of the solid system is conspicuous in Na2CO3 mixtures rather than in K2CO3 or Li2CO3 one. This shows that the order of magnitude of perturbations by the solid phase depends also on the cationic species associated within the system. (C) 2007 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2007年11月, ELECTROCHIMICA ACTA, 53 (1), 71 - 78, 英語[査読有り]
研究論文(学術雑誌)
In this study, we successfully synthesized monodispersed metal oxide nanoparticles of high-temperature phases such as monoclinic VO2, orthorhombic Ta2O5 under an ambient condition without any post-annealing process, applying the liquid phase deposition (LPD) method in the confined system of reverse micelle (RM). It was suggested that the obtained nanoparticles were highly crystallized due to the depression of surface disorder, indicated by Raman spectrum of rutile type SnO2 nanoparticles. This procedure represents a simple route for the production of highly crystallized nanoparticles with potentially interesting applications. (C) 2007 Published by Elsevier Ltd.
PERGAMON-ELSEVIER SCIENCE LTD, 2007年11月, ELECTROCHIMICA ACTA, 53 (1), 179 - 185, 英語[査読有り]
研究論文(学術雑誌)
Terbium (III) ion-doped zirconia (ZrO2:Tb3+) thin films have been directly prepared on soda-lime glass and Si wafer by the liquid phase deposition (LPD) method. The stabilization of Tb3+ ion in the LPD reaction solution, containing fluoride anions, was successfully achieved by using DTPA (diethylenetriaminepentaacetic acid) as a masking reagent. Preparation composition of ZrO2:Tb3+ thin film was determined by inductively coupled plasma-atomic emission (ICP-AES) microscopy analysis. The structural and luminescence properties for the deposited films were analyzed. After annealed at 900 degrees C, the deposited film shows characteristic strong emission assigned to D-5(4)-F-7(5) of Tb3+ under CT band excitation.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2007年10月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 115 (1346), 608 - 611, 英語[査読有り]
研究論文(学術雑誌)
Terbium (III) ion-doped zirconia (ZrO2:Tb3+) thin films have been directly prepared on soda-lime glass and Si wafer by the liquid phase deposition (LPD) method. The stabilization of Tb3+ ion in the LPD reaction solution, containing fluoride anions, was successfully achieved by using DTPA (diethylenetriaminepentaacetic acid) as a masking reagent. Preparation composition of ZrO2:Tb3+ thin film was determined by inductively coupled plasma-atomic emission (ICP-AES) microscopy analysis. The structural and luminescence properties for the deposited films were analyzed. After annealed at 900 degrees C, the deposited film shows characteristic strong emission assigned to D-5(4)-F-7(5) of Tb3+ under CT band excitation.
CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI, 2007年10月, JOURNAL OF THE CERAMIC SOCIETY OF JAPAN, 115 (1346), 608 - 611, 英語[査読有り]
研究論文(学術雑誌)
Organic/inorganic hybrid thin films for protein recognition have been prepared by the liquidphase deposition (LPD) coupled with template synthesis, i.e., molecular imprinting, where pepsin (Pep) was used as a model protein and titanium oxide was deposited on gold substrates in the presence of Pep-Poiy-L-lysine (PL) complexes. The complexes remained in the templated film after the deposition, and the binding sites for Pep were constructured after Pep was removed from the film. Surface plasmon resonance signals on the deposited films were measured to examine the binding behaviors toward proteins. The binding of Pep on the templated film was reversible, and the binding isotherm of Pep depicted a saturation curve with a binding constant of 7.3 x 10(5) M-1, which was 10 times higher than that of albumin. In contrast, titanium oxide films prepared without PL did not show any selectivity; therefore, the hybridization of PL as the organic binder with the inorganic material is necessary to obtain selective binding sites for Pep. It was also shown that the hybridization process should proceed without denaturing the template protein, in order to obtain selective binding sites for the template. The procedure for preparation of the films was simple to perform, and the process for hybridization of the thin films with nanometer-order thickness was easily controlled by changing the LPD reaction time period. Consequently, the proposed LPD coupled with template synthesis is among the most appropriate methods to prepare hybrid materials with protein recognition ability, which proceeds under mild conditions in aqueous solution.
AMER CHEMICAL SOC, 2007年09月, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 129 (35), 10906 - 10910, 英語[査読有り]
研究論文(学術雑誌)
Liquid-phase deposition, LPD, method was used for the fabrication of copper ferrite (CuFe2O4) thin film from aqueous solution system of FeOOH-NH4 . HF (aq.) and Cu source (Cu(NO3)(2) or CuCl2) with H3BO3. SEM observation revealed that highly homogeneous thin film was formed on a substrate. In X-ray diffraction measurements, major peaks assigned to CuFe2O4 was observed in heat-treated films. Quantitative analysis of elements in the deposited films indicated the deposition of CuFe2O4. The kinds of Cu-source did not affect on the deposition. Initial content of Cu2+ could alter the Fe/Cu atomic ratio in deposited film.
CHEMICAL SOC JAPAN, 2007年04月, CHEMISTRY LETTERS, 36 (4), 518 - 519, 英語[査読有り]
研究論文(学術雑誌)
The electrolyte conductivity was measured for the coexisting system containing the non-aqueous lithium electrolyte and lithium cobalt (III) oxide (LiCoO2) powder utilized as the cathode active material. The anomalous behaviors of the ionic conduction near the solid surface were discussed. The conductivity increased with an increase of the liquid content and depended on the solvents. The values of each system depend on the order of the conductivity of bulk systems. Below 15 vol% of the liquid phase, the values were similar as each others. The activation energy was relatively low (20-25 kJ/mol) and decreased with the decrease of the liquid phase for the system containing LiCoO2 powder, whereas the values increased for the system containing α-Al2O3 powder. The decrease phenomena of the activation energy were depends on the solvent species. The IR spectra showed the change of the solvation interaction between C=O bonding and Li+ ion. It is suggested that the conductivity near the solid surface depends on the interaction between solid surface and the ionic species among the solvent molecules. copyright The Electrochemical Society.
2007年, ECS Transactions, 2 (27), 31 - 40, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Platinum nanoparticles/polypyrrole composite was loaded on carbon utilized for catalyst layer in order to improve the electrode durability. The carbon surface was oxidized by potassium permanganate and nitrate acid. Formed acidic functional group on the carbon surface was ion-exchanged by tetraammine platinum hydroxide complex. Loaded platinum complex contributed to the one-step polymerization of pyrrole, and the thin layer of polypyrrole was formed with the thickness of ca.3 nm. The nanolayer of polypyrrole interacted with carbon surface electrostatically and hindered diffusion of the platinum particle oxidized by cathode reaction on the cyclic voltammetry. The catalytic activity was held during durability examination up to 12500 cycles between -0.2-1.0 V vs Ag/AgCl. copyright The Electrochemical Society.
2007年, ECS Transactions, 2 (8), 63 - 72, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The small angle x-ray scattering (SAXS) and wide angle x-ray scattering (WAXS) is measured for RTMS containing aliphatic quaternary ammonium cation [RNMe3]+ (where R=n-CnH2n+1 n=3-16 which are denoted as "N111n") and bis(trifluoromethyl sulfonyl) imide anion. It is shown that a new peak at low q-value is confirmed above n=5. It is suggested that this new peak is of the local ordering structure formed by van der Waals force between alkyl chains of ammonium cations. From DSC result, the local ordering structure forms in [N111n]TFSI above n=8. This behavior is due to the thermal mobility of the alkyl chains of which local ordering structure has a good thermal stability. The other room temperature molten salts such as "[Nnnnn]+(n-5-6), [N1123]+, N-methyl-n-propyl piperidium cation [PPB]+ and N-methyl-n-propyl pyrrolidinium cation [P13]+ having the same anion TFSI- were also used. The layer spacing (d) of this ordering structure is decrease with increase of the temperature. In the [Nnnnn]TFSI (n=5-6) systems, the peak of the local ordering structure is sharply confirmed around q=5 nm-1 and this peak does not shift with increase of the temperature. From SAXS results of RTMSs ([Nnnnn]TFSI (n=5-6), [N1123]TFSI, [PP13]TFSI and [P13]TFSI), the peak around q=7 nm-1 is assigned to the form factor of the electron density around N atom of aliphatic quaternary ammonium cation or the structure factor between the electron density around N atom of aliphatic quaternary ammonium cations. copyright The Electrochemical Society.
2007年, ECS Transactions, 3 (35), 89 - 95, 英語[査読有り]
研究論文(国際会議プロシーディングス)
We have studied a novel technique for the direct synthesis of two-dimensional metal oxide films with highly ordered periodic structure. TiO2 films with highly nano-ordered architectures were directly deposited on substrates at room temperature by the liquid phase infiltration (LPI) method. 2D arrays of several kinds of metal oxide rods with diameters ranging from ca. 100 to 1000 nm are fabricated by filling the holes in a Si wafer. We summarized the various kinds of ordered structured metal oxide thin film with this method and the other techniques which have been reported that a novel soft solution process for the direct synthesis of large-area well-crystallized oxides with 1D-3D ordered periodic structure has been developed based on the LPI method. Metal oxide thin films were deposited directly into the nano-space, and thus the nano-space was completely infiltrated with metal oxide. The LPI process provides a direct fabrication route for metal oxide films with highly ordered structures, enabling nanoscale modification of optical properties of photonic crystals. ©The Electrochemical Society.
2007年, ECS Transactions, 6 (11), 11 - 22, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Transparent Eu3+-doped metal oxide thin films have been directly fabricated on various kinds of substrates by the liquid phase deposition (LPD) method. The stabilization of Eu3+ ion in the LPD reaction solution, containing F- anions, was successfully achieved by using diethylenetriaminepentaacetic acid (DTPA) as a masking regent. The structural and luminescence properties for the deposited films were analyzed. The deposited films consisted of nano-sized spherical particles. The formation of solid-solution was confirmed from the film after annealing above 800 degrees C. The strong excitation peak due to charge transfer (CT) band was observed. After being annealed at 900 degrees C, the deposited film shows characteristic strong emission from Eu3+, D-5(0) -> F-7(2), under CT band excitation. (c) 2005 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2006年02月, JOURNAL OF ALLOYS AND COMPOUNDS, 408, 711 - 716, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
In order to reveal physicochemical anomalies of molten nitrate melts coexisting with inorganic powder, Raman spectra, electrical conductivity and thermal analysis of alpha-Al2O3 powder/molten alkali nitrates coexisting systems were measured. The variations of intramolecular vibration modes of nitrate ion permeated among porous solid material were investigated by means of Raman spectroscopic measurement and IF spectra measured in previous study. The nitrate v, mode varied with the specific surface area of the solid phase and the apparent average thickness of the liquid layer. These variations indicate that the nitrate molecular motions are perturbed by the presence of the alumina powder. The Gaussian resolution of the nitrate v, mode showed a small asymmetry, which is attributed to the presence of bound nitrate ion in higher wavenumber range. Two Raman lines observed in the range from 450 to 350 cm(-1) are assigned to the symmetric stretching v(s)(Al-O) of aluminum nitrate or aluminum nitrite. Although, most of the nitrate ions retained their free D-3h structure, a lowering of symmetry from D-3h to C-2v was observed for samples containing small amount of nitrate with large surface area. These structural changes are in good agreement with some other properties of nitrate melts coexisting with the solid phase, such as the ionic conductivity and the activation energy, and thermal behaviors. The roles of cationic species involved into systems are also discussed. (c) 2005 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2006年01月, VIBRATIONAL SPECTROSCOPY, 40 (1), 66 - 79, 英語[査読有り]
研究論文(学術雑誌)
Monodispersed TiO2 nanoparticles were synthesized by the LPD process using polymer aqueous solution of polyethyleneglycol (PEG) in order to control reactivity of metal-fluoro complex and size of deposited TiO2 particles. Monodispersed well-crystallized anatase particles are found after several minutes and easily separated from the reaction solution. The particle size of obtained samples ranged from ca. 3-5 nm with around 10% of standard deviation values. The synthesizing method presents a new route for preparing well-crystallized metal oxide nanopartcles with potential applications at an ambient condition. copyright The Electrochemical Society.
2006年, ECS Transactions, 3 (9), 29 - 35, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Art nanoparticles dispersed SiO2/TiO2 layered films were prepared by a novel wet process known as the liquid phase deposition method. Their structure, surface morphology, chemical states, particle size and optical properties were investigated by using X-ray diffraction, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, scanning electron microscopy and ultraviolet -visible absorption spectroscopy. An nanoparticles were obtained in the both oxide matrices by the thermal reduction. The XPS studies showed that Au-III and Au-I ionic species were co-deposited in the SiO2/TiO2 layered films. TEM observation revealed that the most of Au nanoparticles were transferred into the crystalline anatase TiO2 matrix after the heat treatment. It was found that, the distributed An nanoparticles were more stable in the crystalline TiO2 than amorphous SiO2 matrix. The mean size of Art in SiO2 (similar to 15 nm) is larger than that of TiO2 (similar to 5 nm) matrix. An absorption peak of Au particles was observed at the wavelength of ca. 570 nm which could be assigned to the surface plasmon absorption band of An nanoparticles. (c) 2005 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2005年11月, THIN SOLID FILMS, 491 (1-2), 86 - 90, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
To develop a preparation method for size-controlled nanoparticles, we applied a liquid-phase infiltration (LPI) method to the reverse micelle (RM) reaction. The average sizes of the nanoparticles were 4.6 and 2.0 nm for TiO2 and FeO, respectively. The size distribution was narrow, and particle crystallization was promoted by the nanoscale reaction field. We have also fabricated the TiO2/Au films with a highly ordered periodic structure by the LPI method using colloidal crystals as a template. The LPI process is conducive to the preparation of advanced nanoceramics with highly ordered structures. (C) 2005 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2005年11月, ELECTROCHIMICA ACTA, 51 (5), 802 - 808, 英語[査読有り]
研究論文(学術雑誌)
To develop a preparation method for size-controlled nanoparticles, we applied a liquid-phase infiltration (LPI) method to the reverse micelle (RM) reaction. The average sizes of the nanoparticles were 4.6 and 2.0 nm for TiO2 and FeO, respectively. The size distribution was narrow, and particle crystallization was promoted by the nanoscale reaction field. We have also fabricated the TiO2/Au films with a highly ordered periodic structure by the LPI method using colloidal crystals as a template. The LPI process is conducive to the preparation of advanced nanoceramics with highly ordered structures. (C) 2005 Elsevier Ltd. All rights reserved.
PERGAMON-ELSEVIER SCIENCE LTD, 2005年11月, ELECTROCHIMICA ACTA, 51 (5), 802 - 808, 英語[査読有り]
研究論文(学術雑誌)
TixSn1-xO2 films with gradient composition profiles have been prepared by the liquid phase deposition method. The crystal structure and composition of these TixSn1-xO2 films were investigated by means of high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray (EDX) analysis with a nano-probe. The gradient profile of the films in the direction of film thickness could be controlled by varying the flow rate. The existence of microcrystalline rutile-SnO2 and anatase-TiO2 was observed near the substrate and the top-surface, respectively. The photocatalytic activity of TixSn1-xO2 films with gradient composition profiles was markedly higher than that of the SnO2/TiO2 multilayer. © 2004 Elsevier B.V. All rights reserved.
Elsevier, 2005年10月01日, Journal of Electroanalytical Chemistry, 584 (1), 38 - 43, 英語[査読有り]
研究論文(国際会議プロシーディングス)
We report on the direct deposition of high-quality ZrO2 thin. films on various kinds of substrates by the liquid phase deposition method. After reaction for 24 h, thin films formed on various kinds of substrates, and the obtained thin film was comprised of densely packed nano-sized particles. The film annealed at 500 degrees C showed a tetragonal phase at room temperature and this phenomenon has been discussed from the viewpoint of crystallite size effect. The result of optical transmittance measurement revealed that high transparency, more than 70% transmittance, has been achieved for the. film after annealing at 900 degrees C.
BLACKWELL PUBLISHING, 2005年10月, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 88 (10), 2923 - 2927, 英語[査読有り]
研究論文(学術雑誌)
We report on the direct deposition of high-quality ZrO2 thin. films on various kinds of substrates by the liquid phase deposition method. After reaction for 24 h, thin films formed on various kinds of substrates, and the obtained thin film was comprised of densely packed nano-sized particles. The film annealed at 500 degrees C showed a tetragonal phase at room temperature and this phenomenon has been discussed from the viewpoint of crystallite size effect. The result of optical transmittance measurement revealed that high transparency, more than 70% transmittance, has been achieved for the. film after annealing at 900 degrees C.
BLACKWELL PUBLISHING, 2005年10月, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 88 (10), 2923 - 2927, 英語[査読有り]
研究論文(学術雑誌)
TixSn1-xO2 films with gradient composition profiles have been prepared by the liquid phase deposition method. The crystal structure and composition of these TixSn1-xO2 films were investigated by means of high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray (EDX) analysis with a nano-probe. The gradient profile of the films in the direction of film thickness could be controlled by varying the flow rate. The existence of microcrystalline rutile-SnO, and anatase-TiO2 was observed near the substrate and the top-surface, respectively. The photocatalytic activity of TixSn1-xO2 films with gradient composition profiles was markedly higher than that of the SnO2/TiO2 multilayer. (c) 2004 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2005年10月, JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 584 (1), 38 - 43, 英語[査読有り]
研究論文(学術雑誌)
In order to discuss the hetero-phase effect of the coexisting solid phase on the ionic conduction in non-aqueous lithium electrolyte solution, the conductivity and transport number of ionic species in non-aqueous lithium perchlorate solution/montmorillonite clay composite system were measured using Hittorf's cell. Transport number of lithium ion rapidly increased as the clay content increased, while total conductivity gradually decreased. The calculated ionic mobility of lithium ion was constant in the liquid content range of 75-90 vol.%. The activation energy of the conductivity for both ions separately obtained from the temperature dependence of the ionic mobilities. The activation energy of lithium ion was ca. 10 kJ mol(-1) and extremely lower than anion species. It is proved that the lithium ion transfer is promoted by the cation exchange materials using inorganic clay materials. It is suggested that the lithium ions can transfer through the inside of clay structure and anion transfer is hindered by the repulsion between anion species and clay skeleton structure. (c) 2005 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2005年08月, JOURNAL OF POWER SOURCES, 146 (1-2), 365 - 370, 英語[査読有り]
研究論文(学術雑誌)
The differential scanning calorimetry was performed in order to discuss the thermochemical properties of room temperature molten salts (RTMSs) coexisting with porous inorganic powders such as alpha-Al2O3, ZrO2, SiO2, and SiC. Whereas the melting point of bulk sample was observed at 25.8 degrees C, it decreased with an increase of the specific surface area of the solid phase. The molar enthalpy of fusion also decreased. It is suggested that the phase transition behavior is influenced by the coexistence of the porous solid phase.
ELECTROCHEMICAL SOC JAPAN, 2005年08月, ELECTROCHEMISTRY, 73 (8), 603 - 605, 英語[査読有り]
研究論文(学術雑誌)
The structure of intermediate-range ordering (IRO) in sodium acetate (CH3COONa) and sodium propionate (C2H5 COONa) melts was investigated by X-ray diffraction (XRD) measurements. A peak of IRO was observed at 0.59 angstrom(-1) and 0.49 angstrom(-1) of Q, (d = 10.7 angstrom and 12.8 angstrom) for anhydrous sodium acetate and sodium propionate melt, respectively. The hexahydrate melts also showed a peak at the same position. The XRD measurements were also performed for mixed melts of anhydrous sodium propionate and sodium acetate in order to investigate the composition dependence of the IRO structure, from which the structure and stability of the IRO was discussed.
ELECTROCHEMICAL SOC JAPAN, 2005年08月, ELECTROCHEMISTRY, 73 (8), 614 - 616, 英語[査読有り]
研究論文(学術雑誌)
[査読有り]
研究論文(国際会議プロシーディングス)
The electrical conductivity was measured for the coexisting system containing the alpha-Al2O3 powder and RTMS, i.e. trimethyl-n-propylammonium bis(trifluoromethylsulfonyl)imide (TMPATFSI) and binary RTMS containing TMPATFSI with addition of 1,1,1-trifluoro-N-[(tiifluoromethyl) sulfonyl] methanesulfonamide (HTFSI) as a proton source; H(x)MPA(1-x)TFSI. For the system containing the inorganic powder and TMPATFSI, the electrical conductivity increased exponentially as the liquid content increased, and depended on the specific surface area of the powder. The conductivity showed the temperature dependence following the VTF (Vogel-Tammann-Fulcher) equation. Since HTFSI does not dissociate in the TMPATFSI and does not contribute to the conduction in the bulk system, the electrical conductivity decreased with the increase of the HTFSI content in the bulk system. However, in the coexisting system, the conductivity increased, and the activation energy decreased with the HTFSI content up to 0.4 of [HTFSI] [HTFSI] + [TMPATFSI]. It is expected that the conductivity is enhanced near the solid surface by the contribution of proton of HTFSI.
ELECTROCHEMICAL SOC JAPAN, 2005年08月, Electrochemistry, 73 (8), 606 - 609, 英語[査読有り]
研究論文(学術雑誌)
The Raman spectra of molten lithium-potassium carbonate (LiKCO3) coexisting with porous inorganic powder were measured. The effect of the surface properties of the solid phase and relationship between the electrical conductivity and phase transition behavior of molten carbonate was discussed. The stretching band of CO32- ion (nu(1)) shifted toward lower wavenumbers with a decrease of the liquid content and an increase of the specific surface area of the solid phase caused by the interaction between ionic species and solid surface. The shift width of wavenumber also depends on the kinds of solid phase. The change of peak position for the system containing alpha-Al2O3 powder is larger than that for the system containing ZrO2 powder. These tendencies correspond to the increase of the activation energy of the conductivity and the decrease of the melting point of the carbonate. For the results of conductivity and thermal analysis, the degree of the anomalous behavior of the molten carbonates by the solid phase was observed in the order of alpha-Al2O3 > gamma-LiAlO2 > ZrO2. It is suggested that the influence of the solid phase on the anomalous properties related to the surface acidity.
ELECTROCHEMICAL SOC JAPAN, 2005年08月, ELECTROCHEMISTRY, 73 (8), 680 - 685, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(国際会議プロシーディングス)
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研究論文(国際会議プロシーディングス)
研究論文(学術雑誌)
研究論文(学術雑誌)
Fe/Ti oxide films with graded composition profiles have been prepared from aqueous metal-fluoro complex solutions by the liquid phase deposition method. Films were deposited from a solution, in which the (NH4)(2)TiF6 solution was added under a controlled flow rate into the FeOOH-(NH4FHF)-H-. solution. Transmission electron microscopy and X-ray microanalysis of the films revealed that the composition and graded profile of the deposited films in depth direction could be controlled by adjusting the mixing conditions of the reacting solution. Along with the change in composition, the microstructure of the films changes from microcrystalline beta-FeOOH at the base to nanocrystalline anatase TiO2 near the surface.
BLACKWELL PUBLISHING INC, 2005年03月, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 88 (3), 731 - 736, 英語[査読有り]
研究論文(学術雑誌)
Fe/Ti oxide films with graded composition profiles have been prepared from aqueous metal-fluoro complex solutions by the liquid phase deposition method. Films were deposited from a solution, in which the (NH4)(2)TiF6 solution was added under a controlled flow rate into the FeOOH-(NH4FHF)-H-. solution. Transmission electron microscopy and X-ray microanalysis of the films revealed that the composition and graded profile of the deposited films in depth direction could be controlled by adjusting the mixing conditions of the reacting solution. Along with the change in composition, the microstructure of the films changes from microcrystalline beta-FeOOH at the base to nanocrystalline anatase TiO2 near the surface.
BLACKWELL PUBLISHING INC, 2005年03月, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 88 (3), 731 - 736, 英語[査読有り]
研究論文(学術雑誌)
研究論文(学術雑誌)
研究論文(学術雑誌)
Hybrid titanium oxide thin films containing surfactants, sodium dodecyl benzylsulfonate and sodium dodecyl sulfate, have been prepared by a novel liquid-phase deposition method. It is a new attempt to prepare organic-inorganic hybrid thin film by this method which usually be applied in preparing metal oxide thin film before. The two kinds of surfactants/TiO2 hybrid thin films were characterized by means of FT-IR, SEM, XRD, fluorescence X-ray, ICP-AES and Raman spectroscopy, and showed noticeable differences in surface top view and particle diameter, cross-section image and thickness, deposited amount of Ti, XRD patterns and Raman shift. The reasons giving rise to above differences of the two kinds composite thin films has been discussed. The deposition mechanism of organic-inorganic hybrid thin film has been also presumed. The use of this processing parameter may open up a new way to the preparing of the organic-inorganic hybrid thin film. (C) 2004 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2005年01月, APPLIED SURFACE SCIENCE, 239 (3-4), 292 - 301, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(国際会議プロシーディングス)
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研究論文(学術雑誌)
The insoluble copper phthalocyanine (CuPc)/TiO2 composite thin film has been successfully prepared in an aqueous solution by liquid-phase deposition (LPD) method, applying two surfactants as the solubilizing agents. The two surfactants are sodium dodecyl benzylsulfonate (SDBS) and sodium lauryl sulfate (SDS), selected as the representative of their groups. The deposited films were characterized by UV-vis, SEM, FT-IR, XRD and ICP-AES. Comparing the two composite thin films, it revealed a series of interesting facts. The films showed excellent adherence to the substrate with particle diameter ranging from 20-50 nm in, and 90 and 280 nm in thickness. It is identified that CuPc is coexisting of dimers, and monomers form, mainly in dimeric form for both the composite thin films by UV-vis spectroscopy, illustrating that the CuPc is not further aggregated by LPD process. The dependences of deposited amount of Ti and Cu with the reaction time suggested the growing of the films can be easily controlled, the SDBS seems to be hindrance to the growing of the films. After heat treatment at 250degreesC for 2 h, the SDS-CuPc/TiO2 thin film becomes crystallized, but no obvious XRD peak is observed in the SDBS-CuPc/TiO2 composite thin film. (C) 2004 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2004年10月, SYNTHETIC METALS, 146 (1), 17 - 27, 英語[査読有り]
研究論文(学術雑誌)
Rare earth-doped TiO2 thin films have been successfully formed on glass and Si wafer substrates from aqueous solution through equilibrium reaction between metal-fluoro complex and metal oxide, in which Ln(3+)-ethylenediaminetetraacetic acid (EDTA) complex (Ln: rare earth metal) was added into the reaction solution. Ln/Ti ratio and crystalline structure of the film could be controlled by varying the initial concentration of Ln(3+)-EDTA complex solution. The obtained Ln-doped films were densely-packed and had no cracks. (C) 2004 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2004年07月, THIN SOLID FILMS, 460 (1-2), 83 - 86, 英語[査読有り]
研究論文(学術雑誌)
Preparation of polypyrrole (PPy) containing Pt nanoparticles was attempted. The oxidation of pyrrole into polypyrrole proceeded by H2PtCl4, simultaneously reducing Pt(IV) to Pt(0). The Pt particles were obtained with average size of 2 nm and fairly narrow size distribution. Moreover, the maximum content of Pt reached over 20 wt% without any evidence of aggregation. The optimum [Pt]/[Py], for obtaining successful Pt/PPy composite including highly concentrated Pt and exhibiting high electrical conductivity, was determined at R = 0.6.
ELECTROCHEMICAL SOC JAPAN, 2004年06月, ELECTROCHEMISTRY, 72 (6), 415 - 417, 英語[査読有り]
研究論文(学術雑誌)
Preparation of polypyrrole (PPy) containing Pt nanoparticles was attempted. The oxidation of pyrrole into polypyrrole proceeded by H2PtCl4, simultaneously reducing Pt(IV) to Pt(0). The Pt particles were obtained with average size of 2 nm and fairly narrow size distribution. Moreover, the maximum content of Pt reached over 20 wt% without any evidence of aggregation. The optimum [Pt]/[Py], for obtaining successful Pt/PPy composite including highly concentrated Pt and exhibiting high electrical conductivity, was determined at R = 0.6.
ELECTROCHEMICAL SOC JAPAN, 2004年06月, ELECTROCHEMISTRY, 72 (6), 415 - 417, 英語[査読有り]
研究論文(学術雑誌)
For the development of the preparation method of size-controlled nanoparticles, we applied the liquid phase deposition (LPD) method to the reverse micelle (RM) reaction contained TritonX-100 and 1-hexanol. We prepared two kinds of metal oxide nanoparticle; TiO2 and SnO2. The average sizes of nanoparticles were 5.9 nm and 3.0 nm for TiO2 and SnO2, respectively. The size distribution was narrow, and crystallization of the particles was promoted by the nanoscale reaction field. The bandgap was calculated from UV-Vis spectra. The bandgap energy of SnO2 nanoparticles showed a larger value at 4.6 eV, whereas that of TiO2 nanoparticles showed a constant value at 3.2 eV. The quantum effect causes the variation of the bandgap, however, the effect depends on the kinds of the metal oxide.
ELECTROCHEMICAL SOC JAPAN, 2004年06月, ELECTROCHEMISTRY, 72 (6), 452 - 454, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(学術雑誌)
A novel technique for the direct synthesis of two-dimensional metal oxide films with highly ordered periodic structure has been studied. The technique involves liquid-phase infiltration (LPI) in an aqueous solution. 2D TiO2 structures with diameters ranging from 120 to 1065 nm are fabricated by filling the holes in a Si wafer using a solution of (NH4)(2)TiF6 and H3BO3 at ambient temperature, and subsequently peeling off the template. Field emission scanning electron microscopy (FESEM) reveals that the resultant TiO2 structures have highly nano-ordered architectures and represent negative and positive replicas of the template. The TiO2 structures are transferred from the template with precision; no voids or seams are introduced during the transfer. The film thickness or filling rate of TiO2 can be controlled by adjusting the reaction time. The LPI process is conducive to the preparation of advanced metal oxide films with highly ordered structures, and enables modification of optical properties of photonic crystals on a nanometer scale.
AMER CHEMICAL SOC, 2004年05月, CHEMISTRY OF MATERIALS, 16 (9), 1747 - 1750, 英語[査読有り]
研究論文(学術雑誌)
In order to clarify the relationship between the structure and ionic conduction behaviour of hydrate melt near the solid surface, several physicochemical properties; such as electrical conductivity, thermal analysis, EXAFS and Raman spectra, of ZnCl2.nH(2)O melt (n = 4/3-6) coexisting with the alpha-Al2O3 fine powder were measured. No transition point of the electrical conductivity was observed around the melting point of ZnCl2 hydrate melt. The value of DeltaE(a) increased up to 50-70 kJ mol(-1), which is greater by ca. 40 kJ mol(-1) than that of the bulk phase. It is suggested that the interaction between the solid and liquid phases influences the phase transition of ZnCl2 hydrate. The DSC measurement for the system consisting of alpha-Al2O3 powder and ZnCl2.4/3H(2)O showed a shift of the melting point toward lower temperatures down to -5degreesC. A decrease of the molar enthalpy of the fusion, DeltaH(m), with a decrease of melt content was observed in this system. The decreased DeltaH(m) is too small to detect the endothermic peak of melting for the system containing powder having a large specific surface area. In this case, a solidification of the hydrate melt was intensively prevented even below the melting point of the bulk system of the solution. However, such a variation was not observed for the system containing alpha-SiC. It is suggested that the Zn(II) dissolved ionic species are influenced by the solid phase, and also depend on the hydrophilicity of the solid surface. For the system containing ZnCl2.nH(2)O (n = 2.5-6), EXAFS spectra show that the dehydration promoted the coexistence of alpha-Al2O3 powder by an intensification of the ionic interaction between Zn(n) and Cl- ions. For the system containing ZnCl2.4/3H(2)O, the structure of the highly aggregated complex was broken as shown in the Raman spectra.
ROYAL SOC CHEMISTRY, 2004年04月, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 6 (8), 1944 - 1951, 英語[査読有り]
研究論文(学術雑誌)
The electrical conductivity and melting behavior of alkali molten carbonates, Li2CO3 and K2CO3, coexisting with oxide particles, gamma-LiAlO2 and MgO, have been investigated. The conductivity was measured by the ac impedance method. The melting of carbonates caused an abrupt change in the electrical conductivity at the transition point, T-t. The value of T-t decreased with decreasing melt content in the heterophase system. The activation energy, DeltaE(a), increased with a decrease of apparent average thickness of the liquid layer. Differential thermal analysis measurements of gamma-LiAlO2/Li2CO3 coexisting systems showed a shift toward lower temperatures for the endothermic peak of fusion of Li2CO3. The molar enthalpy of fusion, DeltaH(m), of the coexisting phase decreased with decreasing apparent average thickness. A correlation between the transition point, Tt, of the electrical conductivity and the melting point of the thermal analysis, T-m, was found for inorganic powder/Li2CO3 coexisting systems. These variations in the properties of carbonates are attributed to the effect of the solid phase. The influence of gamma-LiAlO2 powder on both transport and thermal properties of molten carbonates is greater than that of MgO particles. (C) 2004 The Electrochemical Society.
ELECTROCHEMICAL SOC INC, 2004年, JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 151 (5), E179 - E185, 英語[査読有り]
研究論文(学術雑誌)
Two-dimensional graded metal oxide films with highly ordered periodic structure have been prepared from aqueous metal-fluoro complex solutions by liquid-phase infiltration (LPI) in aqueous solution. Films were deposited from solution, in which a (NH4)(2)TiF6 solution was added at a controlled flow rate in an FeOOH-NH4F.HF solution. Field emission scanning electron microscopy (FE-SEM) reveals that the resultant graded oxide structures have highly nano-ordered architectures and represent negative or positive replicas of the template. Transmission electron microscopy (TEM) and X-ray microanalysis of the films revealed that the present technique enabled wide-range control of the composition and graded profile of the deposited films in the depth direction. Along with the change in composition, the microstructure of the films changes from microcrystalline beta-FeOOH at the base to nanocrystalline anatase-TiO2. The LPI process is conducive to the preparation of advanced nanoceramics with highly ordered structures.
ROYAL SOC CHEMISTRY, 2004年, JOURNAL OF MATERIALS CHEMISTRY, 14 (21), 3127 - 3132, 英語[査読有り]
研究論文(学術雑誌)
The free volume in epoxy resins is strongly connected with the cross-linking process of resin and hardener. In-situ measurements of conventional positron annihilation lifetime spectroscopy (PALS) were carried out to investigate the free volume during post-curing of the epoxy resin system diglycidil ether of bisphenol A (DGEBA) and diethylenetriamine (DETA). Direct comparison with the results of infrared spectroscopy (IR) measurements in the transmission mode was performed. The decrease of the free volume was highly dependent on the composition of resin and hardener, since excess hardener leads to qualitative different curing mechanisms.
TRANS TECH PUBLICATIONS LTD, 2004年, POSITRON ANNIHILATION, ICPA-13, PROCEEDINGS, 445-6, 313 - 315, 英語[査読有り]
研究論文(学術雑誌)
The electrical conductivity and melting behavior of alkali molten carbonates, Li2CO3 and K2CO3, coexisting with oxide particles, gamma-LiAlO2 and MgO, have been investigated. The conductivity was measured by the ac impedance method. The melting of carbonates caused an abrupt change in the electrical conductivity at the transition point, T-t. The value of T-t decreased with decreasing melt content in the heterophase system. The activation energy, DeltaE(a), increased with a decrease of apparent average thickness of the liquid layer. Differential thermal analysis measurements of gamma-LiAlO2/Li2CO3 coexisting systems showed a shift toward lower temperatures for the endothermic peak of fusion of Li2CO3. The molar enthalpy of fusion, DeltaH(m), of the coexisting phase decreased with decreasing apparent average thickness. A correlation between the transition point, Tt, of the electrical conductivity and the melting point of the thermal analysis, T-m, was found for inorganic powder/Li2CO3 coexisting systems. These variations in the properties of carbonates are attributed to the effect of the solid phase. The influence of gamma-LiAlO2 powder on both transport and thermal properties of molten carbonates is greater than that of MgO particles. (C) 2004 The Electrochemical Society.
ELECTROCHEMICAL SOC INC, 2004年, JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 151 (5), E179 - E185, 英語[査読有り]
研究論文(学術雑誌)
The electrical conductivity of LiClO4-EC solution coexisting with the monodisperse spherical SiO2 powder was measured. The composition dependence and the activation energy of the conductivity were discussed. The conductivity depends on the solid/liquid composition, especially impregnating condition in the macro-pore among the spherical particles according to the percolation theory. The inner nano-pore contributes as the conducting path besides the supporting performance for the electrolyte solution.
ELECTROCHEMICAL SOC JAPAN, 2003年12月, ELECTROCHEMISTRY, 71 (12), 1093 - 1095, 英語[査読有り]
研究論文(学術雑誌)
The diffuse reflectance spectra of alpha-Al2O3/molten MNO3 (M = K+, Li+) coexisting systems have been measured for the investigation of the physicochemical properties of molten nitrate at the interface of aluminum oxide. In the region of overtone and combination modes from 3000 to 1700 cm(-1). the absorption band nu(3) + nu(4) decreases with increasing specific surface area of alpha-Al2O3 powder for the potassium mixtures. Gaussian resolution Of nu(3) + nu(4) also exhibits changes in band positions of components with the variation in the alumina specific surface area and the nitrate melt content. The second-order derivative of the spectra in the region from 1700 to 950 cm-I shows a set of peaks at 16,45, 1554-1516, and 1452 cm(-1) characteristic of a coordinated nitrate ion. The peak at 1337 cm(-1) suggests a possible formation of nitrite species. The maxima Of nu(3) + nu(4), nu(1) + nu(2), and nu(1) + nu(4) shift toward lower frequencies with increasing temperature above the nitrate melting point. This information shows that the intramolecular bonds of NO3- are affected. These perturbations are attributed to the effect of the solid phase interacting with the liquid phase. The interaction between solid and liquid phases affects the geometry of the ionic species and, therefore, influences the electrical properties of nitrate ions. (C) 2003 Elsevier Inc. All fights reserved.
ACADEMIC PRESS INC ELSEVIER SCIENCE, 2003年12月, JOURNAL OF COLLOID AND INTERFACE SCIENCE, 268 (2), 413 - 424, 英語[査読有り]
研究論文(学術雑誌)
Au nanoparticle doped Nb2O5 composite films (150 nm thickness) have been prepared by a liquid phase deposition method. The deposited films were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible (UV-vis) absorption spectroscopy. The mean sizes of Au particle varied from 7 to 10 nm after the heat treatment at 200-600 degreesC. The optical absorption spectra of these composite films demonstrated an absorption peak due to surface plasmon resonance of dispersed An nanoparticles. It was found that, with an increase in the heat treatment temperature, the wavelength of the surface plasmon resonance of the Au nanoparticles shifted from 577 to 595 nm. The peak shift of the plasmon band can be explained by the crystallization of Nb2O5 films. (C) 2003 Elsevier B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2003年11月, JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 559, 91 - 98, 英語[査読有り]
研究論文(学術雑誌)
In this work we attempted to prepare binary alloy nanoparticles consisting of Au and Co, which is a typical phase-separation system in a bulk phase diagram, via a vacuum co-evaporation method. The crystal structure and lattice constant of the Au/Co nano-alloys obtained were investigated by means of a high-resolution transmission electron microscope and selected area electron diffraction. We obtained thermodynamically stable Au/Co nano-alloys with A1 structure upon heat-treatment at a certain temperature, and a partial transition from A1 to an ordered L1(0) structure also took place. The results in the present study demonstrated the thermodynamical differences on alloying behavior between bulk and nanoscopic materials. (C) 2003 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2003年11月, JOURNAL OF ELECTROANALYTICAL CHEMISTRY, 559, 99 - 102, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(学術雑誌)
The hetro-structured oxide thin films from metal fluorocomplex solution have been prepared by the liquid phase deposition (LPD) method. The Pt/Nb2O5 and Au/Nb2O5 composite films can be prepared from a mixed solution of mobium source, H3BO3, Pt(NH3)(4)Cl-2 and HAuCl4 aqueous solutions under the ambient temperature and atmosphere. In the case of Au/SiO2 composite film, (NH4)(2)SiF6 solution is used as a mother solution. The Pt and Au ionic species are deposited in Nb2O5 and SiO2 matrices. They are reduced to their metallic state after treatment above 200 degreesC. The size of dispersed particles can be controlled by heat treatment temperature. It is also clear that, gold nanoparticles are also found to interact with SiO2, although the interaction is smaller than that with Nb2O5 showing the size of An nanoparticles remain smaller in Nb2O5 that in SiO2. (C) 2002 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE SA, 2003年04月, JOURNAL OF FLUORINE CHEMISTRY, 120 (2), 157 - 163, 英語[査読有り]
研究論文(学術雑誌)
The transport number of the dissolved species in the lithium electrolyte solutions was measured and the influence of the solid phase to the each dissolving species in the solution. The transport number of lithium ion, t(Li+), was measured by Hittorf's method for the system LiClO4-PC solution in the bulk system and the system coexisting with the alpha-Al2O3 powder. The transport number decreased as the apparent average thickness of the liquid phase decreased. It is suggested that the Li+ ion is influenced from the solid phase more intensively than anions. The apparent ionic mobilities decreased with the thickness of the liquid phase for both ions, however, the Li+ ion was influenced more than ClO4- ion. Consequently, the solid phase influences to each dissolving species separately.
ELECTROCHEMICAL SOCIETY INC, 2003年, BATTERIES AND SUPERCAPACITORS, 549 - 556, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The diffuse reflectance spectra of the alpha-Al2O3/molten NaNO3 coexisting systems have been measured in order to investigate the interactions of nitrate ions with aluminium oxide. alpha-Al2O3 with various specific surface areas (3.00, 10.0, 17.8 and 32.8 m(2) g(-1)) has been used as the solid phase. The liquid content ranged from 10 to 30% of the volume fraction of sodium nitrate. The effect of the solid phase on the nitrate ion absorption bands is discussed in the region of higher wavenumbers ranging from 3000 to 1700 cm(-1). For the system containing particles with a lower melt content, the combination band nu(3) + nu(4) decreases with increasing specific surface area of alumina. This decrease in the band position shows that the nitrate ion structure is influenced by the presence of the solid phase. The variation of fitted band components with the specific surface area corroborates the tendency of the band maxima. It is suggested that both D-3h and C-2v symmetry types of nitrate ion co-exist in such hetero-phase systems. The temperature effect on the spectra of the mixtures is described above the NaNO3 melting point. Spectral measurements have been performed at temperatures up to 723 K. Analysis was carried out above the melting point of sodium nitrate.
ROYAL SOC CHEMISTRY, 2003年, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 5 (10), 2089 - 2095, 英語[査読有り]
研究論文(学術雑誌)
The deposition process of iron oxyhydroxide (beta-FeOOH) from aqueous solution system of FeOOH-(NH4FHF)-H-. (aq.) with H3BO3 by the liquid phase deposition (LPD) method has been investigated. The effect of initial concentration in the treatment solution and reaction time on microstructure and orientation of the deposited films were studied by means of scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM) observation. The films deposited were constructed by small particles having a crown-like and columnar structure, depending on the concentration range in the treatment solution. XRD measurements revealed that the deposited film preferred the specific direction normal to (211) plane and the dimension of the crystallites varied with the initial concentration of the solution. The deposition process and structure of the films appeared to be strongly affected by the hydrolysis reaction of Fe3+ ions coordinated by F- and/or partial OH- ions by adding boric acid. (C) 2002 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 2002年11月, SOLID STATE IONICS, 151 (1-4), 1 - 9, 英語[査読有り]
研究論文(学術雑誌)
AuxCo1 (-) (x) nano-alloys with a diameter below 10 nm were fabricated via a vacuum co-evaporation method. The composition dependence and the effect of heat-treatment on the microstructure of the AuxCo1 (-) (x) nano-alloys were investigated by means of electron diffraction analysis. The lattice constant of fee AuxCo1 (-) (x) nano-alloys varied with the composition and heat-treatment. The results revealed that as-deposited AuxCo1 (-) (x) nano-alloys were in a thermodynamically metastable state, and the following heat-treatment led to their equilibrium state. Furthermore, phase transition from fee solid solution to Ll(0)-type ordered face-centered tetragonal (fct)-structure partially took place during heat-treatment. The temperature and magnetic field dependences of electrical resistivity were investigated for polyacrylonitrile (PAN) thin films embedded with AuxCo1 (-) (x) nano-alloys, and a TMR value of 80% was obtained at room temperature under appropriate conditions.
ROYAL SOC CHEMISTRY, 2002年08月, JOURNAL OF MATERIALS CHEMISTRY, 12 (8), 2408 - 2411, 英語[査読有り]
研究論文(学術雑誌)
We have prepared polyacrylonitrile (PAN) thin films containing Au nanoparticles by heat treatment of Au/PAN stacking films. The effect of heat treatment on the microstructure of the composite films was investigated by means of transmittance electron microscopy (TEM), Fourier-transform infrared (FT-IR) and Raman spectroscopy. The Au nanoparticles initially deposited on the PAN film were found to be dispersed into the PAN layer by heat treatment at 200°C, after which structural changes in the PAN matrix were observed, i.e. decomposition of methylene and nitrile groups into C=N conjugation. It was also found that heat treatment of the films at higher temperatures caused change of the PAN matrix into amorphous carbon. The mean size of the Au nanoparticles increased with increasing heat-treatment temperature. © 2002 Elsevier Science B.V. All rights reserved.
2002年04月, Thin Solid Films, 408 (1-2), 59 - 63[査読有り]
研究論文(学術雑誌)
Pt nanoparticle-doped Nb2O5 composite films (similar to80 nm thickness) have been prepared by the liquid phase deposition method. The deposited films were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FT-IR). Heat treatment of the deposited films above 200 degreesC under airflow produced dispersion of the Pt particles. The mean sizes of the Pt particles varied from 2 to 6 nm after heat treatment at 300-600 degreesC. All deposited films were X-ray amorphous up to 500 degreesC of heat treatment, above which a crystalline structure appeared. The crystallized composite film corresponded to the hexagonal structure of TT-Nb2O5.
ROYAL SOC CHEMISTRY, 2002年, JOURNAL OF MATERIALS CHEMISTRY, 12 (5), 1495 - 1499, 英語[査読有り]
研究論文(学術雑誌)
The electrical conductivity was measured for the coexisting system containing the alpha-Al2O3 powder and RTMS, i. e. trimethyl-n-propyl ammonium bis(trifluoromethylsulfonyl)imide(TMPA-TFSI) and binary RTMS which containing TMPATFSI added HTFSI as a proton source; H/TMPA-TFSI. For the system containing the inorganic powder and TMPATFSI, the electrical conductivity increased exponentially as the liquid content increased, and depended on the specific surface area of the powder. The conductivity showed the temperature dependence following the VTF (Vogel-Tammann-Fulcher) equation. Whereas the melting point of bulk sample was observed at 25.8degreesC, it decreased with an increase of the specific surface area of the solid phase. The molar enthalpy of fusion also decreased. It is suggested that the phase transition behavior is influenced by the coexistence of the porous solid phase. Since HTFSI does not dissociate in the TMPATFSI and does not contribute to the conduction in the bulk system, the electrical conductivity decreased with the increase of the HTFSI content in the bulk system. However, in the coexisting system, the conductivity increased and the activation energy decreased with the HTFSI content up to 0.4 of [H+]/cation. It is expected that the conductivity is enhanced near the solid surface by the contribution of proton of HTFSI.
ELECTROCHEMICAL SOCIETY INC, 2002年, MOLTEN SALTS XIII, 2002 (19), 954 - 963, 英語研究論文(国際会議プロシーディングス)
Au nanoparticles dispersed SiO2-TiO2 composite films have been prepared by a novel wet process, Liquid Phase Deposition (LPD) method. The composite films were characterized by XRD, XPS, TEM, ICP, SEM and UV-VIS absorption spectroscopy. The results showed that the SiO2-TiO2 composite films containing Au-III and Au-I ionic species were co-deposited from a mixed solution of ammonium silicofluoride, ammonium hexafluorotitanate, boric acid and tetrachloroauric acid. The heat treatment induced the reduction of Au ions and formation of Au nanoparticles in the film. TEM observation revealed that tho Au nanoparticles with 5-10 nm in diameter were found to be dispersed uniformly in the SiO2-TiO2 matrix. The optical absorption band due to the surface plasmon resonance of dispersed Au particles were observed at the wavelength of 550 run and shifted toward longer wavelength with increasing heat treatment temperature.
SPRINGER-VERLAG, 2001年09月, EUROPEAN PHYSICAL JOURNAL D, 16 (1-3), 325 - 328, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(学術雑誌)
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研究論文(学術雑誌)
The electrical conductivity and melting behavior of binary molten carbonate, (Li, Na)(2)CO3 and (Li, K)(2)CO3 coexisting with gamma-LiAlO2 powder were studied. The electrical conductivity was measured by the ac impedance method. Observed transition temperatures corresponding to fusion of carbonates were lower than that of the melting point of each carbonate and it lowered as the liquid content decreased. The electrical conductivity did not diminish even below the temperature of the melting point. Since the conductivity is much larger than that of pure gamma-LiAlO2 powder, it can be presumed that a part of the carbonate does not frozen and the conduction path is kept through the carbonate. The value of DeltaE(a) depends on the parameter; "the apparent average thickness of the liquid phase", obtained by the calculation; [total volume of the liquid phase]/[total surface area of the solid phase]. The value of DeltaE(a) increases as the apparent average thickness decreases. It is suggested that the electrical conduction of the carbonate was intensively influenced by the solid phase. The decrease of the liquid phase and the increase of the specific surface area of the solid phase relatively strengthen the influence of the solid phase. The application of the molten salts by coexisting the porous solid materials is expected as the semi-solid ionic conducting materials at the temperature range below the melting point.
SHANGHAI UNIV, 2001年, PROCEEDINGS OF THE 6TH INTERNATIONAL SYMPOSIUM ON MOLTEN SALT CHEMISTRY AND TECHNOLOGY, 101 - 106, 英語[査読有り]
研究論文(国際会議プロシーディングス)
A novel technique for the direct synthesis of Si1-xTixO2 thin films with graded composition profiles has been studied in aqueous solution, in which the (NH4)(2)SiF6 solutions were added into the (NH4)(2)TiF6 master solution under time- and rate-controlled reaction conditions: the composition of the films in the direction of the film thickness was successfully controlled over a wide range by this technique.
ROYAL SOC CHEMISTRY, 2001年, JOURNAL OF MATERIALS CHEMISTRY, 11 (4), 984 - 986, 英語[査読有り]
研究論文(学術雑誌)
A complex of polymer, plasticizer and Lithium salts can be used as a solid gel polymer electrolyte in lightweight and rechargeable lithium batteries. Considerable research has been directed towards the development of a gel polymer with high conductivity at room temperature. In this work, a gel polymer electrolyte using polyvinylidene fluoride (PVdF)-1000. (KF), a plasticizer of 1:1 ethylene carbonate (EC) and propylene carbonate (PC), and LiBF4 salt is optimized. Gel electrolytes have high ionic conductivity, good mechanical stability, a wide electrochemical stable window, and a stable lithium interface. The results of preliminary charge-discharge of cells are discussed in detail. (C) 2000 Elsevier Science S.A. All rights reserved.
ELSEVIER SCIENCE SA, 2000年06月, JOURNAL OF POWER SOURCES, 88 (2), 269 - 273, 英語[査読有り]
研究論文(学術雑誌)
Composite thin films consisting of nano-sized Ag particles dispersed in nylon 11 thin films have been prepared by using a thermal relaxation technique. The films obtained were characterized by transmission electron microscopy (TEM), electron diffraction (ED), energy-dispersive X-ray (EDX) microanalysis, and optical absorption spectroscopy. The Ag nanoparticles with 4.5-9.1 nm in diameter were found to be isolated individually and dispersed uniformly in the nylon 11 matrix. The volume fraction and the mean size of Ag nanoparticles in the film could be controlled by varying the initial amount of Ag deposition. Optical absorption peak due to the surface plasmon resonance of the Ag particles were observed around 430 nm and shifted to a longer wavelength with increasing the mean size of Ag nanoparticles, and absorbance increased simultaneously. We have also prepared Ag2S nanoparticles with 4.7-11.2 nm in diameter in nylon 11 films from exposing the Ag/nylon 11 films to H2S/O2 mixed gas. ED patterns of the particles formed after the reaction with H2S were completely indexed as those of β-Ag2S with a monoclinic structure. The onset of the optical absorption spectra is similar to that of bulk β-Ag2S, suggesting that Ag2S nanoparticles with diameter of ca. 5 nm preserve the band structure of bulk Ag2S.
2000年01月24日, Thin Solid Films, 359 (1), 55 - 60[査読有り]
研究論文(学術雑誌)
Structural change of Zn2+ ion with mole fraction of Li+ and Ca2+ ion is investigated by X-ray diffraction measurement, laboratory EXAFS, and Raman spectroscopy for molten ZnCl2. 6H(2)O-LiCl . 3H(2)O and ZnCl2. 6H(2)O-CaCl2. 6H(2)O systems. For neighboring structure of zinc ion, an octahedral structure with six water molecules, [Zn(H2O)(6)](2+) varies to a tetrahedral structure with four chloride ions, [ZnCl4](2-) with increasing of mole fraction of lithium and calcium ion. The lithium ion remains as a tetrahedral structure with four water molecules. An octahedral structure with water molecules or a chloride ion is observed for the calcium ion. The correlation among the cations, chloride ion and water is discussed on the composition dependence of the structure for the mixed molten hydrate systems.
ELECTROCHEMICAL SOCIETY INC, 2000年, MOLTEN SALTS XII, PROCEEDINGS, 99 (41), 263 - 274, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The electrical conductivity of heterogeneous systems consisting of alpha-Al2O3 and 1.0 mol/l LiClO4 solution was measured using various kinds of organic solvents, such as propylene carbonate(PC), ethylene carbonate(EC), gamma-butyrolactone(GBL), and PC-1,2-dimethoxyethane (DME), and water. The composition dependence and temperature dependence of the conductivity were measured and the influence of the solid phase was discussed. The electrical conductivities normalized by those of the parent solutions showed the different composition dependence for each system. The activation energy of the electrical conductivity increases and depends on the viscosity of each parent solution. For the binary mixed solvent PC-DME system, the dependence of the electrical conductivity of the solvent composition was discussed. The DME content at which the maximum values of the conductivity of the solution were observed was shifted from ca. 0.6 to ca. 0.2 with a decrease of the liquid content and an increase of the specific surface area of the solid phase. The electrical conductivity of the lithium electrolyte solution coexisting with the solid phase was intensively influenced by the interaction between solid and liquid phases. The conductivity of the solid/liquid coexisting system depends not only on the species of the solvent and its compositions, but also on the content and the surface area of the solid phase.
ELECTROCHEMICAL SOCIETY INC, 2000年, LITHIUM BATTERIES, PROCEEDINGS, 99 (25), 463 - 470, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The electrical conductivity of the co-existing system containing inorganic powder, either gamma-LiAlO2 or MgO, and lithium carbonate was measured by the ac impedance method. The abrupt change in electrical conductivity caused by the melting of the carbonate was observed at the transition point, T-t. The value of T-l decreased, as the melt content decreased in the co-existing system. The activation energy of the electrical conductivity, Delta E-a, was calculated from the temperature dependence of the conductivity, i. e., Arrhenius plots. The value of Delta E-a increased with a decrease in the apparent average thickness of the liquid phase ( = [total volume of the liquid phase]/[total surface area of the solid phase]) in the system. The melting behavior of Li2CO3 co-existing with inorganic powder was observed by means of differential thermal analysis (DTA). The endothermic peak of the fusion of Li2CO3 shifted toward lower temperature. The molar enthalpy of fusion, Delta H-m, of the carbonate co-existing with the inorganic powder decreased, as the apparent average thickness of the liquid phase also decreased. The variations in the properties of the molten carbonate were caused by the co-existence of the inorganic powder. The influence of gamma-LiAlO2 powder was larger than that of MgO powder for both properties of conductivity and melting behavior.
ELECTROCHEMICAL SOCIETY INC, 2000年, MOLTEN SALTS XII, PROCEEDINGS, 99 (41), 292 - 300, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Raman spectra were measured for the system consisting of alpha-Al2O3 powder and aqueous electrolyte solution of LiNO3, NaNO3, CH3COOLi, and CH3COONa, in order to discuss a hetero-phase coexisting effect of the solid phase on the properties of the Liquid phase. The Raman bands assigned to the stretching mode of OH2 at 2800-4000 cm(-1) was distorted by the heterophase coexisting effect, and the distortion depended on the dissolved anionic species. The distortion for the system containing acetate anions, which have hydrophobic and hydrophilic groups, was different from those for the other systems, i.e. pure water and aqueous nitrate solutions as the liquid phase. The NO3- symmetric stretching mode (nu(1)) of nitrate anion at ca. 1045 cm(-1), the COO stretching mode of (nu(3)) at ca. 1415 cm(-1), and the C-C stretching mode (nu(4)) at ca. 925 cm(-1) of acetate ion were also measured and the changes of their position are discussed. Each Raman band shifted and broadened with the content and specific surface area of the solid phase from the original position and shift for the bulk of each aqueous solution. It is suggested that the intra-molecular structure of ionic species is influenced by the existance of solid surface. The hetero-phase coexisting effects, caused by the solid phase, mainly depend mainly on the nature of anionic species in the system. (C) 1999 Elsevier Science B.V. All rights reserved.
ELSEVIER SCIENCE BV, 1999年12月, JOURNAL OF MOLECULAR LIQUIDS, 83 (1-3), 179 - 189, 英語[査読有り]
研究論文(学術雑誌)
Many types of polymer electrolytes have been developed and characterized in the past few years. Recently special attention has been focussed on the development of gel polymer electrolytes consisting of host polymers such as PAN, PVC, PVP PVS, PMMA, PEGDA and PVdF etc., as they may find unique applications in consumer electronic and electric vehicle products. In the present study, gel polymer electrolytes have been prepared using the solvent casting technique in the presence of PVdF-1015 (SOLEF), EC + PC as a plasticizer, and LiBF4 salt. The influence of the amount of polymer, plasticizer and LiBF4 on the gel electrolytes has been studied using XRD, DSC, AC impedance and charge-discharge studies. (C) 1999 Elsevier Science PV All rights reserved.
ELSEVIER SCIENCE BV, 1999年11月, SOLID STATE IONICS, 126 (3-4), 285 - 292, 英語[査読有り]
研究論文(学術雑誌)
We have prepared nano-sized Au/Pd bimetallic particles with various compositions dispersed in nylon 11 thin films by thermal relaxation technique. The films obtained were characterized by TEM, EDX, XPS and visible absorption spectroscopy. The Au/Pd molar ratio in the bimetallic particles could be varied over the entire composition range by controlling the initial deposition amount of constituent metals. It was found that the mean size of the dispersed particles decreased from 5.3 to 3.2 nm in diameter with increasing the Pd content in the bimetallic particles. Optical absorption due to surface plasmon resonance absorption of the Au particles decreased with decreasing the Au/Pd ratio, which can be caused by the changes in the band structure of the Au particles due to alloying with Pd. (C) 1999 Acta Metallurgica Inc.
PERGAMON-ELSEVIER SCIENCE LTD, 1999年02月, NANOSTRUCTURED MATERIALS, 11 (1), 59 - 65, 英語[査読有り]
研究論文(学術雑誌)
Nano-sized copper(I) oxide particles dispersed in nylon 11 thin films have been prepared by a thermal relaxation technique. The obtained composite films were characterized by XRD, HRTEM, XPS, AES and UV-VIS absorption spectroscopy. Upon heat treatment under air, metallic copper initially deposited on the nylon 11 surface penetrates into the bulk phase of the nylon 11 as Cu2O particles. The mean size of the Cu2O particles increased from 3.2 to 6.3 nm in diameter upon increasing the amount of Cu deposition. UV-VIS spectroscopy revealed that the absorption increased from as low as 600 nm with increasing the size and the concentration of the dispersed Cu2O particles.
ROYAL SOC CHEMISTRY, 1998年08月, JOURNAL OF MATERIALS CHEMISTRY, 8 (8), 1865 - 1868, 英語[査読有り]
研究論文(学術雑誌)
Electrical conductivity and thermodynamic properties of the coexisting system consisting of ZnCl2. nH(2)O(n = 1.33 - 2.50) melt and alpha-Al2O3 or alpha-SiC were measured. No transition point of the electrical conductivity was observed around the melting point of ZnCl2 hydrate melt. The value of Delta E increased up to 50-70 kJ/mol, which is greater by ca. 40 kJ/mol than thai of the bulk phase. It is suggested that the interaction between the solid and liquid phases influences the phase transition of ZnCl2 hydrate. The DSC measurement for the system consisting of alpha-Al2O3 powder and ZnCl2. 1.33H(2)O showed a shift of the melting toward lower temperatures up to 0 degrees C. A decrease of the molar enthalpy of the fusion, Delta H-m, was observed in this system. The decreased Delta H-m is too small to detect the endothermic peak of melting for the system containing powder having a large specific surface area. In this case, a solidification of the hydrate melt was intensively prevented even below the melting point of the bulk system of the solution. However, such Variation was not observed for the system containing alpha-SiC. it is suggested that the Zn(II) dissolved species are extremely influenced by the solid phase and have a tendency of forming a different structure from that of bulk systems. Therefore the melting behavior is influenced by the hydrophilicity of the solid surface.
ELECTROCHEMICAL SOCIETY INC, 1998年, PROCEEDINGS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON MOLTEN SALTS XI, 98 (11), 513 - 520, 英語[査読有り]
研究論文(国際会議プロシーディングス)
For several sodium n-alkanecarboxylate hydrous melts (CnK2n+1 COONa . RH2O, n=0,1,2,3,4,5,7,9), the structural change with carbon number in the alkyl group was investigated by X-ray diffraction measurements. A peak was found over 10 Angstrom of d-value (d= lambda/2 sin theta) for the hydrous melts (n= 1,2,3,4,5,7,9) except sodium formate (n=0), which suggested the evidence of the middle-range structure. The peak position was not varied with the water content, while the peak intensity increased with decreasing of the water content The peak position shifted to lower angle region with increasing carbon number in the alkyl group. It was found that the dimension of the middle-range structure was affected by the carbon number, the hydrophobicity of the carboxylate anion. The d-value of the peak position was proportional to the carbon number with slope of 2.7 Angstrom /carbon. It was assumed that the middle range structure is similar to micelle-like structure in the anhydrous sodium carboxylate melts.
ELECTROCHEMICAL SOCIETY INC, 1998年, PROCEEDINGS OF THE ELEVENTH INTERNATIONAL SYMPOSIUM ON MOLTEN SALTS XI, 98 (11), 521 - 526, 英語[査読有り]
研究論文(国際会議プロシーディングス)
Iron oxyhydroxide thin films have been prepared from the aqueous solution system of FeOOH-NH4F . HF (aq.) with added boric acid by a novel liquid-phase deposition (LPD) method and is the first attempt to preparate iron oxide thin films by this method. A crystalline beta-FeOOH thin film was formed directly on the substrate upon immersion into a mixed solution of FeOOH-NH4F . HF and H3BO3. The orientation of the deposited film differed according to the concentration of H3BO3 in the solution. When the concentration of H3BO3 was >0.30 mol dm(-3), the beta-FeOOH thin film was preferentially oriented in the [211] direction. The beta-FeOOH thin film formed was transformed into alpha-Fe2O3 upon heat treatment in air how. The alpha-Fe3O3 thin films obtained were oriented in the [110] direction. The F content of the as-deposited beta-FeOOH film was ca. 15% F/Fe and was reduced to 0.19% upon heat treatment.
ROYAL SOC CHEMISTRY, 1997年09月, JOURNAL OF MATERIALS CHEMISTRY, 7 (9), 1769 - 1772, 英語[査読有り]
研究論文(学術雑誌)
The quartz crystal microbalance (QCM) technique has been applied to investigate the formation of titanium oxide thin films by the liquid-phase deposition (LPD) method. A linear relationship was observed between the thickness measured by the QCM technique and that measured by direct observation with a scanning electron microscope, indicating that it is possible to monitor the growth of thin films from aqueous solution systems by the LPD method with the QCM technique. The concentration effects of free F-, H3BO3 and (NH4)(2)TiF6 on the film deposition rate are discussed.
ROYAL SOC CHEMISTRY, 1997年05月, JOURNAL OF MATERIALS CHEMISTRY, 7 (5), 733 - 736, 英語[査読有り]
研究論文(学術雑誌)
Au-dispersed TiO2 (anatase) thin films have been prepared by a novel method, liquid-phase deposition (LPD). The deposited films were characterized by XRD, XPS, TEM and UV-VIS absorption spectroscopy. The results showed that the titanium oxide thin him containing Au-III ions was formed from a mixed solution of ammonium hexafluorotitanate, boric acid and tetrachloroauric acid. Heat treatment above 200 degrees C of the deposited film under flowing air produced dispersed Au metal particles, accompanied by the crystallization of titanium oxide as a matrix. The mean particle size of the dispersed Au particles was ca. 15 nm. The optical absorption band due to the surface plasmon resonance of the dispersed Au particles shifted toward longer wavelengths with increasing heat-treatment temperature.
ROYAL SOC CHEMISTRY, 1996年12月, JOURNAL OF MATERIALS CHEMISTRY, 6 (12), 1879 - 1882, 英語[査読有り]
研究論文(学術雑誌)
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研究論文(学術雑誌)
Ion-exchange method was studied to deposit platinum particles on carbon support for preparing a gas-diffusion electrode for fuel cell. Carbon black powder or sheet containing polytetrafluoroethylene as a binder was firstly oxidized to form active functional groups. The ion-exchange was performed by immersing the oxidized carbon support in a solution dissolved platinum cation complex such as Pt(NH3)(6)Cl-4 and Pt(NH3)(4)Cl-2. The impregnation method using trinitro-diammine platinum nitrate was also studied. In both methods, the resultant platinum particles were highly dispersed on the surface of carbon black. The fuel cell using electrodes catalyzed by these techniques showed higher performance than that catalyzed by a conventional impregnation method
DECHEMA, 1996年, HYDROGEN ENERGY PROGRESS XI, VOLS 1-3, 1933 - 1938, 英語[査読有り]
研究論文(国際会議プロシーディングス)
The deposition of platinum on various carbon blacks has been carried out by forming active functional groups on the surface of the carbon support, and exchanging these active groups with different platinum complexes. Using H2PtCl6 solution, an aggregation rather than an exchange takes place. In this case, the anionic platinum complexes [PtCl6](2-) involved have a tendency to form a coagulated platinum cluster after the reduction process. However, using ammonium platinum chloride, an exchange between the cationic platinum complexes and surface functional groups takes place. The exchange process involving the divalent platinum complex, [Pt(NH3)(4)](2+) is much faster than the one where the tetravalent platinum complex [Pt(NH3)(6)](4+), is involved. Transmission electron migrograph (TEM) photographs have shown that when using Pt(NH3)(4)Cl-2 solution for the exchange, platinum particles are extremely small (0.75-1.7 nm) and highly dispersed on the surface of the carbon black. A comparison of the catalytic activities of platinum supported on various carbon blacks was also carried out. The catalytic activity mainly depends on the particle size rather than the loading amount of the catalyst.
ROYAL SOC CHEMISTRY, 1995年12月, JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS, 91 (24), 4451 - 4458, 英語[査読有り]
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Solid polymer electrolyte was applied to CO2 reduction. A zero-gap system with an anion exchange membrane and a porous PTFE sheet deposited solid electrolyte, and a water supply system from the anodic side by back-diffusion through the membrane were effective in the reaction.
PERGAMON-ELSEVIER SCIENCE LTD, 1995年06月, ENERGY CONVERSION AND MANAGEMENT, 36 (6-9), 629 - 632, 英語[査読有り]
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The effects of such bath conditions as reducing agent concentration, Ni salt concentration and plating temperature on the rate of electroless Ni plating by the reducing agent permeation method were examined.
At the initial nucleus formation stage, it was supposed that the mutual diffusion of BH4- and Cl- through the membrane was the rate determining step and the initial nucleus formation rate was proportional to the 0.2 power of NaBH4 concentration and NiCl2 concentration. The activation energies of the diffusion coefficients of both anious were calculated to be 4.57kJ/mol.
At the Ni growth stage, it was estimated that in addition to the nutual anion diffusion, Ni diffusion was also the rate determining step.
The rate of Ni growth was proportional to the 0.3 power of the NaBH4 concentration and the 0.7 power of the NiCl2 concentration. The activation energy of the rate constant was calculated to be 3.90kJ/mol. The rate of Ni growth can be controlled by these kinetic parameters.
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Effect of solid phase on various properties of binary alkali molten carbonates, (LixK1-x)(2)CO3, coexisting with inorganic powder such as alpha-Al2O3, ZrO2, gamma-LiAlO2 and MgO by means of measurements of the electrical conductivity, DTA, and Raman spectroscopy were reviewed. The melting of carbonates caused an abrupt change in the electrical conductivity at the transition point, T,. The value of T, decreases with decreasing melt content in the hetero-phase system. The activation energy, Delta E-a increases with a decrease of apparent average thickness of the liquid layer. Differential thermal analysis (DTA) measurements of the gamma-LiAlO2/Li2CO3 Systems show a shift toward lower temperatures for the endothermic peak of fusion of L2CO3. The molar enthalpy of fusion, Delta H-m, of the coexisting phase decreases with decreasing apparent average thickness. A correlation between the transition point, T-t, of the electrical conductivity and the melting point of the thermal analysis, T-m, is found for inorganic powder/Li2CO3 systems. These variations in the properties of carbonates are attributed to the effect of the solid phase. The influence of gamma-LiAlO2 powder on both transport and thermal properties of molten carbonates is greater than that of MgO particles. The Raman stretching band of CO32- ion (nu(1)) shifts toward lower wavenumber with a decrease of the liquid content and an increase of the specific surface area of the solid phase for the system containing LiKCO3/inorganic powder. The shift width of wavenumber also depends on the kinds of solid phase. The change of peak position for the system containing alpha-Al2O3 powder is larger than that for the system containing ZrO2 powder.
METALLURGICAL INDUSTRY PRESS, 2005年10月, JOURNAL OF RARE EARTHS, 23 (Special Issue), 1 - 15, 英語[査読有り]
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ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(基調)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(基調)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(基調)
ポスター発表
ポスター発表
ポスター発表
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
口頭発表(基調)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
その他
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
ポスター発表
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
[招待有り]
口頭発表(招待・特別)
[招待有り]
口頭発表(招待・特別)
ポスター発表
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
ポスター発表
ポスター発表
ポスター発表
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
ポスター発表
ポスター発表
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
[招待有り]
口頭発表(招待・特別)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
ポスター発表
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
口頭発表(一般)
American Chemical Society
Royal Society of Chemistry
International Society of Electrochemistry
The Electrochemical Society
日本コンピュータ化学会
応用物理学会
日本希土類学会
日本セラミックス協会
電気化学会
日本化学会
競争的資金
競争的資金
競争的資金
競争的資金
競争的資金
本研究ではPEFCカソードにおけるPt/PPy on Cの耐久性の評価を目的とし, 膜-電極接合体(MEA)にPt/PPy on Cを用い, Pt on C系での結果と比較を行った. 初期においては、Pt, Pt/PPyいずれも電極の活性が認められたが、1000回掃引において活性の低下が認められ、10000回後にはPtのみ担持した場合殆どPtによる活性は認められなくなっていた。一方、Pt/PPyの場合は白金/ポリピロールコンポジットにおける電極活性は保持されていることが明らかとなった。次にPtの溶出状態について検討するため, カソード側MEA界面における断面TEM観察を行った. これより, Pt/PPy on CはPt on Cに比較しNafion膜中に溶出・再析出したPtは殆ど観察されなかった.Pt/PPy on C はPt on Cに比較しPtの凝集が抑制されていることが確認された.以上の結果より, 実際の発電条件においてもPt/PPy on CはPtのNafion膜中への溶出防止が可能であり, さらにPt微粒子の凝集抑制効果を有することが明らかとなった.
競争的資金
競争的資金
競争的資金
競争的資金
水溶液中からの遷移金属酸化物薄膜の合成法である、液相析出(LPD)法を用いて、ジルコニアに希土類元素(Ln=Y、La)を添加し、ジルコニア薄膜の安定化及び得られた薄膜の伝導性材料への応用の可能性を検討した。ZrO_2薄膜の製膜には、H_2ZrF_6水溶液にフッ化物イオン捕捉剤として金属アルミニウムを浸漬した水溶液を用いた。ここに、Laイオンの安定化のためにEDTAとLnCl_3(Ln=Y、La)を1:1の比で混合し、Ln-EDTA錯体とした水溶液を添加し、処理溶液とした。この処理溶液中に基板を垂直懸下し、30℃で所定時間静置反応させた。反応後、Y、La系とも基板上に白濁した薄膜を得た。希土類元素の初期濃度が高くなるに伴い凝集粒子サイズが小さくなっていく傾向が確認された。これは、希土類元素の濃度が高くなるとZrO_2薄膜の析出が阻害されるため、核生成段階での反応が抑制されたためと考えられる。Y-Zr系におけるYCl_3の初期濃度を変化させた際のX線回折パターンより初期濃度が増加するに伴ってZr
競争的資金
アルミニウム置換α型水酸化ニッケルの製造方法
特願2008-283734, 2008年11月04日, 大学長, 特開2010-111522, 2010年05月20日, 特許5339346, 2013年08月16日特許権
ナノオーダーサイズの三次元周期構造体を有した三次元構造体2
特願2008-020250, 2008年01月31日, TLO, 特開2009-178808, 2009年08月13日, 特許5334090, 2013年08月09日特許権
ナノオーダーサイズの三次元周期構造体を有した三次元構造体
特願2008-020249, 2008年01月31日, TLO, 特開2009-178807, 2009年08月13日, 特許5334089, 2013年08月09日特許権
膜状蛍光発光体およびその製造方法
特願2009-265608, 2009年11月20日, 大学長, 特開2011-105919, 2011年06月02日, 特許5327635, 2013年08月02日特許権
複合微細構造体およびその製造方法
特願2007-075356, 2007年03月22日, 大学長, 特開2008-230925, 2008年10月02日, 特許5150898, 2012年12月14日特許権
イオン液体を用いたカチオン伝導媒体およびイオン液体中のカチオン伝導度向上方法
特願2005-147137, 2005年05月19日, 大学長, 特開2006-324144, 2006年11月30日, 特許5140822, 2012年11月30日特許権
基板型ガス検知素子およびガス感応層の構成粒子の製造方法
特願2008-151898, 2008年06月10日, 大学長, 特開2009-300107, 2009年12月24日, 特許5010541, 2012年06月08日特許権
標的分子のセンサー素子およびその製造方法
特願2006-131913, 2006年05月10日, 大学長, 特開2007-303938, 2007年11月22日, 特許4820999, 2011年09月16日特許権
セラミックス基板又は無機耐熱性基板の洗浄方法及びこれを用いた素子の製造方法並びに素子
特願2007-064926, 2007年03月15日, TLO, 特開2008-224498, 2008年09月25日, 特許4848504, 2011年08月31日特許権
貴金属系触媒担持導電性高分子複合体およびその製造方法
特願2005-373455, 2005年12月26日, 大学長, 特開2007-175558, 2007年07月12日, 特許4797166, 2011年08月12日特許権
ナノ粒子およびナノ粒子の製造方法
特願2006-223664, 2006年08月18日, 大学長, 特開2008-044826, 2008年02月28日, 特許4765074, 2011年06月24日特許権
希土類含有金属酸化物構造体の製造方法
特願2005-077724, 2005年03月17日, TLO, 特開2006-256916, 2006年09月28日, 特許4682321, 2011年02月18日特許権
水素ガスセンサに用いられる薄膜状の金属酸化物イオン伝導体の製造方法
特願2004-125442, 2004年04月21日, 財団法人新産業創造研究機構, 特開2005-308529, 2005年11月04日, 1970-01-01, 2010年07月23日特許権
貴金属系触媒担持炭素化物の製造方法及び貴金属系触媒担持炭素化物
特願2004-261784, 2004年09月09日, 大学長, 特開2006-075709, 2006年03月23日, 特許4423420, 2009年12月18日特許権
液相析出法によるマイクロパターニング方法
特願2003-123184, 2003年04月28日, 財団法人新産業創造研究機構, 特開2004-323946, 2004年11月18日, 1970-01-01, 2009年05月22日特許権
貴金属系触媒担持導電性高分子複合体の製造方法
特願2003-156814, 2003年06月02日, 国立大学法人神戸大学, 特開2004-359724, 2004年12月24日, 1970-01-01, 2005年12月02日特許権
白金ニトロアンミン系錯体の製造方法
特願平6-336206, 1994年12月22日, 独立行政法人産業技術総合研究所, 石福金属興業株式会社, 特開平8-176175, 1996年07月09日, 1970-01-01, 2004年02月13日特許権
燃料電池用ガス拡散電極の製造方法
特願平6-329806, 1994年12月06日, 独立行政法人産業技術総合研究所, 石福金属興業株式会社, 特開平8-162122, 1996年06月21日, 1970-01-01, 2003年07月18日特許権
非水電解質二次電池用負極および該負極を備えた非水電解質二次電池
特願2009-223296, 2009年09月28日, 国立大学法人岩手大学, 国立大学法人神戸大学, 特開2011-071064, 2011年04月07日特許権
炭素−半金属酸化物複合材料及びその製造方法、ならびに、これを用いたリチウムイオン電池用負極
特願2009-223295, 2009年09月28日, 国立大学法人神戸大学, 国立大学法人岩手大学, 特開2011-071063, 2011年04月07日特許権
還元性ガスセンサに用いられる薄膜状の金属酸化物イオン伝導体の製造方法
特願2004-125442, 2004年04月21日, 財団法人新産業創造研究機構, 特開2005-308529, 2005年11月04日特許権
ナノオーダサイズのセラミックス又はセラミックス前駆体の三次元構造体及びLPD法による作製方法
特願2002-298161, 2002年10月11日, 財団法人新産業創造研究機構, 特開2004-131338, 2004年04月30日, 1970-01-01特許権