Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/d3ta03288d

DOI： 10.1039/d3ta03288d

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.50988/hess.46.2_71

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (research society, symposium materials, etc.)  

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsomega.3c00322

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS  

アルカリ交換膜型水電解用アノード触媒を開発し、その触媒活性と電子状態を評価した。
担当部分：電極触媒の設計と評価

DOI： 10.1021/acscatal.2c02586

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ECS  

DOI： 10.1149/1945-7111/ac624b

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

DOI： 10.1016/j.jcat.2022.02.009

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.jpowsour.2022.230997

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS  

多孔性カーボン表面へのPt担持状態と微細構造、アイオノマー分布を詳細解析し、発電性能との相関を明らかにした。

DOI： 10.1021/acsaem.1c02836

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

PtCoSn合金を担持したTa-SnO2触媒の酸素還元活性の温度依存性、耐久性を評価した。性能向上メカニズムをDFT計算にて明らかにした。

DOI： 10.1016/j.electacta.2021.138894

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ECS  

Pt担持カーボン触媒での単セル性能を評価すると共に、触媒層中のアイオノマーの分布を新たな手法で解析し、性能との相関を明らかにした。

DOI： 10.1149/1945-7111/abfa59.

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS  

DOI： 10.1021/acscatal.0c05157

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS  

DOI： 10.1021/acs.cgd.0c01249

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS  

各種カーボンを用いたPt触媒を用いたセル性能と触媒の微細構造の相関を明らかにした。。

DOI： 10.1021/acsaem.0c02841

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

DOI： 10.1016/j.jpowsour.2020.229407

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ECS  

NiCoナノ粒子を分散したSDC水素極を用いた可逆作動SOCの性能を評価した。

DOI： 10.1149/1945-7111/abbdd8

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ACS  

DOI： 10.1021/acsaem.0c00993

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

高活性・高耐久性を両立するカソード触媒層の設計のため, 高電位安定担体の設計指針と性能との関係を明らかにした。

DOI： 10.11351/jsaeronbun.50.1549

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Americal Chemical Society  

In the case of a Pt catalyst supported on the semiconducting oxide Nb-doped
SnO2 with a fused-aggregate network structure (Pt/Nb-SnO2) for polymer
electrolyte fuel cells, the electronic conductivity increased abruptly with
increasing Pt loading, going from 10−4 to 10−2 S cm−1. The XPS at low Pt loading amount exhibited higher binding energy than that of pristine Pt metal. The peak shift for the Pt XPS spectra was larger than that of the Pt hard HAXPES spectra. For all of the spectra, the peaks approached the binding energy of pristine Pt metal with increasing Pt loading. The Sn XPS spectral peak proved the existence of Sn metal with increasing Pt loading, and the peak intensity was larger
than that for HAXPES. These spectroscopic results, together with the scanning transmission electron microscopy with energy dispersive X-ray spectroscopy (STEM-EDX) spectra, proved that a PtSn alloy was deposited at the interface between Pt and Nb-SnO2 as a result of the sintering procedure under dilute hydrogen atmosphere.

DOI： 10.1021/acsami.9b11119

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

SOFC/SOEC用電極材料（La0.43Ca0.37Ni0.06Ti0.94O3-y、La0.43Ca0.37Ni0.03Fe0.03Ti0.94O3-y)ナノ粒子を合成し、各印加電圧におけるインピーダンスの経時変化を測定すると共に、表面の劣化過程を分析した。

DOI： 10.1016/j.electacta.2019.03.126

Language：Japanese   Publishing type：Research paper (scientific journal)  

静電スプレー法によりPt担持Ta-SnO2触媒を用いた触媒層を作製し、その空隙とセル性能との相関を明らかにした。

DOI： 10.11351/jsaeronbun.50.90

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

Pt/Nb-SnO2触媒層の微細構造・界面構造と発電性能との相関及び耐久性について明らかにした。

DOI： 10.11351/jsaeronbun.50.84

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MPDI  

異原子価陽イオンを置換固溶したSnO2に酸化イリジウムを担持し、酸化イリジウム＋Pt混合電極より高い酸素発生反応を示すことをチャンネルフロー電極法及び単セルにて明らかにした。

DOI： 10.3390/catal9010074

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

Pt担持Nb-SnO2を触媒層とした単セルにて電流印加時における負荷変動試験を実施し、市販Pt担持カーボン触媒より耐久性が高いこと、電子空乏層がPtの溶解を抑制することを明らかにした。

DOI： 10.1149/2.0591816jes

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

DOI： 11.1149/2.0141815jes

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

Ptを担持したNb-SnO2触媒層のアイオノマー添加量・空隙体積及びセル性能との相関を解明し、発電性能の向上メカニズムを明らかにした。さらに、負荷変動試験を実施し、市販触媒より高耐久性を示すことを明らかにした。

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramics Society of Japan  

We have evaluated double-layer hydrogen electrodes with catalyst layers (CLs) and current-collecting layers (CCLs) in order to apply them in proton-conducting solid oxide cells. The scaffolds of the CLs were fabricated from a composite of mixed protonically-electronically conductive (MPEC) perovskite oxide BaCe0.50Zr0.27Y0.20-Ni0.03O3-δ (BCZYN) and Ni on a BaCe0.10Zr0.70Y0.20O3-δ electrolyte. Both powders were synthesized via a flame oxide-synthesis method and both had a unique microstructure, i.e., a fused-aggregate network structure [BCZYN(fans), Ni(fans)]. This unique structure was constructed from both a network of particles fused with their nearest neighbors and pores surrounded by the fused particles. This structure was found to be favorable for constructing both electronically conductive pathways and gas diffusion pathways in the CLs. Highly dispersed Ni nanoparticles [Ni(np)] were also loaded on the MPEC of BCZYN(fans) in the CLs. Composite CCLs of micrometer-sized BaCe0.50Zr0.30Y0.20O3-δ and Ni were also fabricated on the CLs. The catalytic activity of a hydrogen electrode using a CL comprising a composite of BCZYN(fans) and Ni(fans) was higher than that of a CL comprising BCZYN(fans) at a Ni(np) loading amount of 30vol.% due to the improvement of the electronic conductivity in CLs by Ni(fans). The catalytic activity of the hydrogen electrode using the CLs increased with increases in the Ni(np) loading amount, moreover, and reached saturation at around 30vol.% due to relief from the effect of the depletion layer on the outer surface of BCZYN(fans).

DOI： 10.2109/jcersj2.17258

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

For the large-scale commercialization of polymer electrolyte fuel cells (PEFCs), it is very important to reduce the amount of Pt by developing highly efficient cathode catalyst layers (CLs) due to the high cost and limited availability of Pt resources. We investigate the effects of high oxygen permeability ionomers and ion exchange capacity (IEC) on the cathode performance and durability of PEFCs. The high oxygen permeability ionomers are expected to increase the flux of oxygen near the Pt surface of the three-phase boundary, which is critical in the case of extremely low Pt loadings. The low Pt loading cathode CLs are prepared from the AB250-supported Pt catalyst. From the current-voltage (I-E) curve measurements, the high oxygen permeability ionomers improve the cathode performance without any adverse effects. During durability testing, the high IEC ionomers lead to increased solubility of Pt and cause severe Pt agglomeration and a large amount of redeposition of Pt particles in the membrane. Based on these results, we propose a strategy of ionomer property selection to improve both cell performance and durability.

DOI： 10.1149/2.0071806jes

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

Pt3Niエアロジェル触媒をPEFCのアノードに応用し、水素枯渇に対するセルの耐久性・発電性能を評価した。

DOI： 10.1149/2.0531802jes

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

We synthesized Pt and PtRu catalysts supported on Ta-doped SnO2 (Pt/Ta-SnO2, PtRu/Ta-SnO2) for the anodes of direct oxidation fuel cells fueled with poly-oxymethylene-dimethylether (POMMn, n = 3 similar to 8). The onset potential for the oxidation of the hydrolyzed fuel of POMM3 (h-POMM3; methanol-formaldehyde mixtures with the composition equivalent to 100% hydrolyzed POMM3) on Pt/Ta-SnO2 and PtRu/Ta-SnO2 was at least 0.2 V lower than that on a commercial Pt2Ru3/carbon black (c-Pt2Ru3/CB). The Pt-based mass activities at 0.50 V (MA(0.50V)) of PtRu/Ta-SnO2 for the h-POMM3 and formaldehyde oxidations were more than four times larger than those of the c-Pt2Ru3/CB. Elemental tin was found to exist on the top surface, brought by the diffusion from the Ta-SnO2 support. The elemental tin may contribute to enhancing the anodic reaction via an acceleration of carbon monoxide oxidation by a bifunctional mechanism or ligand effect. Single cells using Pt/Ta-SnO2 and PtRu/Ta-SnO2 as anodes exhibited higher current densities in all voltage regions when supplied with the h-POMM3 fuels dissolved in water. We deduced that both the elemental tin diffusion from the Ta-SnO2 support to the catalyst nanoparticles and the unique fused-aggregate network structure of the Ta-SnO2 support contribute to enhancing the performance of POMMn-based fuel cells. (C) The Author(s) 2017. Published by ECS. All rights reserved.

DOI： 10.1149/2.1461712jes

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Chemical Society  

Searches for new electrode materials for batteries must take into account financial and environmental costs to be useful in practical devices. The sol gel chemistry has been widely used to design and implement new concepts for the emergence of advanced materials such as hydride organic inorganic composites. Here, we show that the simple reaction system including titanium alkoxide and water can be used to stabilize a new class of electrode materials. By investigating the crystallization path of anatase TiO2, an X-ray amorphous intermediate phase has been identified whose local structure probed by the pair distribution function, H-1 solid-state NMR and density functional theory (DFT) calculations, consists of a layered type structure as found in the lepidocrocite. This phase presents the following general formula Ti-2_x square O-x(4_4),(OH)(4x) center dot nH2O (x similar to 0.5) where the substitution of oxide by hydroxide anions leads to the formation of titanium vacancies (square) and H2O molecules are located in interlayers. Solid-state H-1 NMR has enabled us to characterize three main hydroxide environments, Ti square-OH, Ti-2 square(2)-OH, and Ti-3 square-OH, and layered H2O molecules. The electrochemical properties of this phase were investigated vs lithium and were shown to be very promising with reversible capacities of around 200 mAh.g(-1) and an operating voltage of 1.55 V. We further showed that the lithium intercalation proceeds via a solid-solution mechanism. Li-7 solid-state NMR and DFT calculations allowed us to identify lithium host sites that are located at the titanium vacancies and interlayer space with lithium being solvated by structural water molecules. The easy fabrication, the absence of lithium, easier recycling, and the encouraging properties make this class of materials very attractive for competitive electrodes for batteries. We thus demonstrate that revisiting an "old" chemistry with advanced characterization tools allows one to discover new materials of technological relevance.

DOI： 10.1021/acs.chemmater.7b02674

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

DOI： 10.3390/catal7070223

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

In order to reduce the amount of noble metal catalysts for the oxygen evolution reaction (OER) in polymer electrolyte membrane water electrolysis (PEMWE) while maintaining high efficiency, we synthesized new catalysts: IrOx nanoparticles dispersed on Nb-SnO2 and Ta-SnO2 supports with fused-aggregate structures. IrOx nanoparticles with a uniform size of ca. 2 nm were highly dispersed on these supports. The OER activities were evaluated by linear sweep voltammetry (LSV) in 0.1 M HClO4 at 80 degrees C using a channel flow electrode cell. The IrOx/Ta-SnO2 catalysts exhibited an apparent mass activity (MA) of 15 A mgIr(-1) for the OER at 1.5 V vs. RHE, which was 32 times higher than that of a conventional catalyst (mixture of Pt black and IrO2 powders). This suggests a possible reduction of the loading of the noble metal anode catalyst to a level as low as 0.1 mg cm(-2) at a voltage efficiency of 90% at 1 A cm(-2). (C) The Author(s) 2017. Published by ECS.

DOI： 10.1149/2.1101709jes

Web of Science

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI AG  

Nickel nanoparticles loaded on the electron-protonmixed conductor BaCe(0.5)Zr(0.3-x)Y(0.2)NixO(3-delta) (Ni/BCZYN, x = 0 and 0.03) were synthesized for use in the hydrogen electrode of a proton-conducting solid oxide electrolysis cell (SOEC). The Ni nanoparticles, synthesized by an impregnation method, were from 45.8 nm to 84.1 nm in diameter, and were highly dispersed on the BCZYN. The BCZYN nanoparticles, fabricated by the flame oxide synthesis method, constructed a unique microstructure, the so-called "fused-aggregate network structure". The BCZYN nanoparticles have capability of constructing a scaffold for the hydrogen electrode with both electronically conducting pathways and gas diffusion pathways. The catalytic activity on Ni/BCZYN (x = 0 and 0.03) catalyst layers (CLs) improved with the circumference length of the Ni nanoparticles. Moreover, the catalytic activity on the Ni/BCZYN (x = 0.03) CL was higher than that of the Ni/BCZYN (x = 0) CL. BCZYN (x = 0.03) possesses higher electronic conductivity than BCZYN (x = 0) due to the Ni doping, resulting in an enlarged effective reaction zone (ERZ). We conclude that the proton reduction reaction in the ERZ was the rate-determining step on the hydrogen electrode, and the reaction was enhanced by improving the electronic conductivity of the electron-proton mixed conductor BCZYN.

DOI： 10.3390/cataol7070223

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

We have developed high-performance double-layer (DL) hydrogen electrodes for reversible solid oxide cells. The DL hydrogen electrode consisted of mixed conductor, samaria-doped ceria (SDC), with highly dispersed Ni or Ni-Co nanocatalysts as the catalyst layer (CL) and, on top of it, a thin Ni-SDC cermet as the current collecting layer (CCL). The performance of the DL hydrogen electrode was appreciably improved by controlling the microstructure. The use of a thin, porous CCL increased the electronic conducting path to and from the CL, while maintaining sufficient gas-diffusion rates of H-2 and H2O, and enlarging the effective reaction zone at the CL. The optimum CCL thickness was found to be 5 mu m. The IR-free overpotentials eta at the optimized DL hydrogen electrode in humidified hydrogen (p[H2O] = 0.4 atm) and T-cell = 800 degrees C were 0.20 and -0.20 V at j = 0.5 and -0.5 A cm(-2), respectively, indicating a highly reversible operation. The use of a full cell with the configuration of Ni0.9Co0.1/SDC DL hydrogen electrode vertical bar YSZ electrolyte vertical bar SDC interlayer vertical bar LSCF-SDC O-2 electrode led to very promising results for the SOEC operation in which an IR-free electrolytic cell potential of 1.21 V at j = -0.5 A cm(-2) and 800 degrees C was achieved. (C) The Author(s) 2017. Published by ECS.

DOI： 10.1149/2.0241709jes

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELECTROCHEMICAL SOC INC  

To reduce the Pt loadings in cathode catalysts for polymer electrolyte fuel cells, we focused on the catalyst material and catalyst-layer (CL) fabrication method, and prepared low Pt loading CLs with Pt/Ta-SnO2 by the electrospray (ES) method. Two CLs were prepared by the ES method with different mass ratios of ionomer binder to support material (I/S), I/S = 0.7 and 0.2, and are compared to that prepared by the pulse-swirl-spray (PSS) method. Both ES CLs have higher porosity than that for the PSS CL, and have improved ionomer coverage and increased electrochemically active surface area (ECA) and mass activity at 0.85 V. In particular, that for the ES with I/S = 0.2 has high porosity and remarkably increased cell performance. The improvement obtained by use of the ES method can be explained on the basis that the coverage and uniformity of ionomer are increased due to the small droplet size. The performance of the ES cells is high, particularly under high backpressure conditions, because of the improved transport of both O-2 and protons. ES is an attractive method for the reduction of the Pt loading while improving cell performance. (C) The Author(s) 2017. Published by ECS. All rights reserved.

DOI： 10.1149/2.0251704jes

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

The use of a hydrogen purge for startup and shutdown (H-2-SU/SD) process of polymer electrolyte fuel cells has been proposed, which suppresses the generation of internal current during the SU/SD, process so-called "reverse current", and the severe carbon oxidation reaction (COR) in the cathode. However it was found that the COR was still caused during this H-2-SU/SD process, even though it was less severe than that during the usual SU/SD process, i.e., the anode gas was successively cycled between air and H-2. In order to clarify the mechanisms of the COR, we investigated (1) the effect of the presence of Pt catalyst, (2) the timing, and (3) the effect of Pt oxidation state. These results indicated that the COR was accelerated by the Pt catalyst in the cathode and was decelerated with increasing cathode potential during the H-2-SU/SD process. We propose that the COR is caused by a shortage of protons associated with both the reduction of the Pt oxide and the oxygen reduction reaction at the reduced Pt. (C) The Author(s) 2017. Published by ECS. All rights reserved.

DOI： 10.1149/2.0101704jes

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

In order to establish clear criteria for designing highly active and highly durable oxygen electrode for reversible solid oxide fuel cells, we have focused on the effect of samaria-doped ceria (SDC) interlayers prepared on YSZ solid electrolyte surface on the performances of La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF)-SDC composite oxygen electrode. Symmetrical cells with the configuration, LSCF-SDC vertical bar SDC interlayer vertical bar YSZ vertical bar SDC interlayer vertical bar LSCF-SDC, were constructed. We prepared two kinds of SDC interlayers, one from a mixed solution of cerium 2-ethylhexanoate (denoted as octoate) and samarium octoates (o-interlayer) and another from a mixed solution of cerium and samarium nitrates (n-interlayer). The LSCF-SDC electrodes with o-interlayer and n-interlayer exhibited very similar performances in both the anodic and cathodic reactions at 900 degrees C. When temperature was decreased to 800 degrees C, an increase in overpotentials was observed. However, the LSCF-SDC electrode with o-interlayer exhibited superior performance to that with n-interlayer. It was found that the entire surface of the YSZ electrolyte disk was well covered with a dense o-interlayer of uniform thickness. Such an interlayer enables uniform transport of oxide ions to and from the LSCF-SDC electrode, resulting in an enlarged effective reaction zone (ERZ). The I-E performance of the LSCF-SDC vertical bar o-interlayer vertical bar YSZ cell was found to be comparable to that of the identical electrode prepared on a dense SDC sintered electrolyte disk (as a reference). This observation supports our views regarding the essential role of a dense interlayer with uniform thickness in enhancing the performance of reversible solid oxide cells. (C) 2016 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2016.12.100

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI  

We have examined the long-term durability of a La0.6Sr0.4Co0.2Fe0.8O3-delta (LSCF)-samaria-doped ceria (SDC) composite oxygen electrode with SDC interlayer for reversible solid oxide cells (R-SOCs). A symmetrical cell with the configuration: LSCF-SDC vertical bar SDC interlayer vertical bar yttria-stabilized zirconia (YSZ) electrolyte vertical bar SDC interlayer vertical bar LSCF-SDC, was operated at 900 degrees C and a constant current density of 0.5 A cm(-2) with the top electrode as the anode (O-2 evolution). The IR-free overpotentials at both the anode and cathode were virtually constant during 5500 h of operation. The value of ohmic resistance at the anode side (R-A) increased slightly, whereas that at the cathode side (R-C) increased markedly. The I-E performance of the bottom electrode (operated as the cathode), that was measured from -1.0 to 1.0 A cm(-2) every 1000 h, degraded specifically at high current densities. It was found that the thickness, pore size, and porosity in both electrodes were unchanged, but the distribution of the Sr component changed markedly at both the LSCF-SDC/SDC interlayer and SDC interlayer/YSZ interfaces. While the diffusion of the Sr component from the anode was limited within the SDC interlayer, the Sr component from the cathode reached the SDC interlayer/YSZ interface, which could increase the R-C, likely due to the formation of SrZrO3. However, the diffusion rates of Sr were found to be noticeably slowed down at dense portions of the SDC interlayer. Hence, it is essential to prepare a dense, uniform SDC interlayer to improve both the durability and performance of R-SOCs. (C) 2017 The Ceramic Society of Japan. All rights reserved.

DOI： 10.2109/jcersj2.16274

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：0013-4651  

DOI： 10.1149/2.0571602jes

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

エレクトロスプレー法により、Pt担持量を従来より少なくしたPt担持カーボン触媒層を作製し、その性能を評価した。

DOI： 10.1149/2.0611610jes

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

We focus on Pt degradation occurring during fuel cell vehicle (FCV) combined drive cycles involving load and open circuit voltage (OCV) just after startup and during idling. Load cycle durability is evaluated as a function of OCV/load holding time, load rate and relative humidity (RH) with a graphitized carbon black supported platinum catalyst (Pt/GCB) in the cathode. The degradation of Pt/GCB is suppressed for shorter OCV holding times, lower load rates and lower RH. Scanning ion microscopy (SIM) images of membrane cross-sections indicate that the amount of Pt deposited in the membrane decreases during drive cycles involving load with short OCV holding times. Investigations of the Pt distribution in the cathode catalyst layer (CL) by using scanning TEM-EDX show that the dissolution of Pt is suppressed on the membrane side in the CL. The Pt dissolution is accelerated by the high Pt oxidation due to the long OCV holding time. A load cycle with both long OCV holding time and low load inhibits the Pt2+ migration into the membrane but accelerates the Pt particle growth due to electrochemical Ostwald ripening; meanwhile, a load cycle with long OCV holding time at lower RH prevents both the Pt dissolution and particle growth. (C) 2016 The Authors. Published by Elsevier B.V.

DOI： 10.1016/j.jpowsour.2016.05.117

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

PEFCにおけるガス置換サイクル試験でのPt担持カーボン触媒の耐久性について検討した。

DOI： 10.1149/2.0771607jes]

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

We investigate the effects of the carbon supports on the Pt distribution, ionomer coverage and cathode performance of carbon-supported Pt catalysts, by using STEM observation, N-2 adsorption analysis and electrochemical characterization. According to the STEM observation, the effective Pt surface area (S(e)(Pt)), which is determined by the location and size of the Pt particles on the supports, increases in the following order: c-Pt/CB < c-Pt/GCB < n-Pt/AB800 < n-Pt/AB250. The N-2 adsorption analyses show that the Pt particles observed in the interior of the CB and AB800-supported Pt catalysts during the STEM observation could be ascribed to the hollow structures inside the carbon supports, which decrease their effective Pt surface areas. The S(e)(Pt) values are in good agreement with the cell performance in the high current density region. In spite of the highest Pt utilization (U-Pt) value (>90%) and uniform ionomer coverage, the c-Pt/CB catalyst shows the lowest cell performance due to the lower S(e)(Pt) value. On the other hand, the n-Pt/AB250 catalyst, for which all of the Pt particles exist only on the exterior surface, is found to be the most attractive in order to generate the large current densities required by actual fuel cell operation. (C) 2016 The Authors. Published by Elsevier B.V.

DOI： 10.1016/j.jpowsour.2016.02.091

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：0013-4651  

Pt担持Nb-SnO2触媒層のインピーダンス測定を行い、セル電圧と触媒層の抵抗との相関と触媒海面の電子状態変化との相関を明らかにした。

Language：Japanese   Publishing type：(MISC) Introduction and explanation (scientific journal)  

カーボン及びセラミックス担体を用いたPt担持触媒の活性、構造、それを用いたセル性能を解説した

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MDPI  

We have prepared Pt nanoparticles supported on titanium carbide (TiC) (Pt/TiC) as an alternative cathode catalyst with high durability at high potentials for polymer electrolyte fuel cells. The Pt/TiC catalysts with and without heat treatment were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). Hemispherical Pt nanocrystals were found to be dispersed uniformly on the TiC support after heat treatment at 600 degrees C in 1% H-2/N-2 (Pt/TiC-600 degrees C). The electrochemical properties (cyclic voltammetry, electrochemically active area (ECA), and oxygen reduction reaction (ORR) activity) of Pt/TiC-600 degrees C and a commercial Pt/carbon black (c-Pt/CB) were evaluated by the rotating disk electrode (RDE) technique in 0.1 M HClO4 solution at 25 degrees C. It was found that the kinetically controlled mass activity for the ORR on Pt/TiC-600 degrees C at 0.85 V (507 A g(-1)) was comparable to that of c-Pt/CB (527 A g(-1)). Moreover, the durability of Pt/TiC-600 degrees C examined by a standard potential step protocol (E = 0.9 V1.3 V vs. RHE, holding 30 s at each E) was much higher than that for c-Pt/CB.

DOI： 10.3390/catal5020966

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

We propose a new strategy for alleviating the reverse current phenomenon using a unique "atmospheric resistive switching mechanism" (ARSM) of a metal oxide semiconductor support, such that the electrical resistivity changes depending on the gas atmosphere. The membrane-electrode assembly (MEA) using Ta-doped TiO2-supported platinum (Pt/Ta TiO2) as the anode catalyst showed approximately one order of magnitude greater resistance in air than in hydrogen. The overpotential of the hydrogen oxidation reaction was negligible up to at least 1.5 A cm(-2). The losses of electrochemically active surface area and carbon corrosion of the cathode catalyst during air/air startup cycling were significantly suppressed by the use of the Pt/Ta-TiO2 anode. The decrease in the degradation is attributed to a reduction of the reverse current due to a low oxygen reduction reaction rate at the anode, which showed high resistivity in air. These results demonstrate the effectiveness of the ARSM in mitigating cathode catalyst degradation during air/air startup cycling. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jpowsour.2015.06.072

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society  

The single cell performances of polymer electrolyte fuel cells (PEFCs) using Pt catalyst supported on Nb-SnO2 (Pt/Nb-SnO2) with/without graphitized carbon black (GCB) were compared with that of a cell using Pt/GCB. The Pt-mass specific power of the Pt/Nb-SnO2 cathode under low humidity conditions was superior to that of the Pt/GCB cathode, because the hydrophilic SnO2 support helped to increase the proton conductivity of the iononner, which led to high Pt effectiveness. The addition of GCB to the Pt/Nb-SnO2 cathode improved the cell performance under high humidity, and the Pt-mass specific power value reached more than 10 kW g(Pt)(-1). The improvement conditions was attributed to the formation of gas diffusion paths by adding the hydrophobic GCB. The Pt/Nb-SnO2 cathodes, with/without GCB, had greater durability than that of the Pt/GCB cathode during the startup / shutdown potential sweep evaluation. The migration of Pt particles on the Nb-SnO2 support was suppressed by the high stability of Nb-SnO2 and. strong orientation between Pt and Nb-SnO2 support. The degradation of GCB in the Pt/Nb-SnO2 cathode was smaller than that in the Pt/GCB cathode because of the absence of Pt on the added GCB. Therefore, the added GCB was still able to provide gas diffusion paths even after extensive cycling. (C) 2015 The Electrochemical Society. All rights reserved.

DOI： 10.1149/2.0651507jes

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The performance of practical-sized membrane-electrode assemblies (MEAs) using titanium nitride-supported platinum (Pt/TiN) as the cathode catalysts was evaluated with the use of a practical single cell designed for microscale combined heat and power (CHP) applications. The performance can be controlled by adding acetylene black (AB), with the behavior being dominated by the percolation law. The electrical resistance of the MEAs drastically decreased for AB contents greater than 37 vol%. The Pt utilization percentage was close to 100% for Pt/TiN with percolated AB networks. It was also found that the percolated AB networks supplied effective gas transport pathways, which were not flooded by generated water, thus enhancing the oxygen mass transport. The practical-sized MEA using Pt/TiN + 47 vol% AB showed 1.5 times greater mass activity and a comparable performance under a practical operating condition for micro-CHP applications, compared with the MEA using a commercial graphitized carbon black-supported platinum catalyst. (C) 2015 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jpowsour.2015.01.132

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

側鎖の異なるアイオノマー を用いたPt担持触媒層を作製し、そのセル性能とアイオノマーの構造との相関を検討した。

DOI： 10.1016/j.jpowsour.2014.10.149

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE INC  

We evaluated the cathodic activity and durability of Pt/Ta-SnO2-delta catalysts for the cathodes of polymer electrolyte fuel cells (PEFCs). The Ta-SnO2-delta support had a unique fused aggregated structure, for which the electrical conductivity was ca. 40 times higher than that of another candidate high-durability support, Nb-SnO2-delta with the same support structure. The kinetically controlled current density value at 0.85 V for Pt/Ta-SnO2-delta reached 0.97 mA cm(-2), which was higher than that for a commercial Pt/CB. Chemical stability of Ptfra-SnO2-delta in the high potential range (0.9-1.3 V) was the same as that of the high-durability Pt/Nb-SnO2-delta catalyst and was superior to that of commercial Pt/CB and Pt/GCB. We demonstrated that the more highly electrically conductive Pt/Ta-SnO2-delta is an attractive catalyst for the construction of low-resistance catalyst layers of membrane-electrode assemblies with decreased overpotentials. Thus, we conclude that the Pt/Ta-doped SnO2-delta catalyst is a superior cathode candidate catalyst for PEFCs. (C) 2014 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.elecom.2014.12.005

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：AMER CHEMICAL SOC  

We synthesized Pt and PtRu catalysts supported on Nb-doped SnO2-d (Pt/Sn0.99Nb0.01O2-delta, PtRu/Sn0.99Nb0.01O2-delta) for direct oxidation fuel cells (DOFCs) using poly oxymethylene-dimethyl ether (POMMn, n = 2, 3) as a fuel. The onset potential for the oxidation of simulated fuels of POMMn (methanol-formaldehyde mixtures; n = 2, 3) for Pt/Sn0.99Nb0.01O2-delta and PtRu/Sn0.99Nb0.01O2-delta was less than 0.3 V vs RHE, which was much lower than those of two commercial catalysts (PtRu black and Pt2Ru3/carbon black). In particular, the onset potential of the oxidation reaction of simulated fuels of POMMn (n = 2, 3) for PtRu/Sn0.99Nb0.01O2-delta sintered at 800 degrees C in nitrogen atmosphere was less than 0.1 V vs RHE and is thus considered to be a promising anode catalyst for DOFCs. The mass activity (MA) of PtRu/Sn0.99Nb0.01O2-delta sintered at 800 degrees C was more than five times larger than those of the commercial catalysts in the measurement temperature range from 25 to 80 degrees C. Even though the MA for the methanol oxidation reaction was of the same order as those of the commercial catalysts, the MA for the formaldehyde oxidation reaction was more than five times larger than those of the commercial catalysts. Sn from the Sn0.99Nb0.01O2-delta support was found to have diffused into the Pt catalyst during the sintering process. The Sn on the top surface of the Pt catalyst accelerated the oxidation of carbon monoxide by a bifunctional mechanism, similar to that for Pt-Ru catalysts.

DOI： 10.1021/am505553b

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

温度、湿度コントロールチャンバーを用いたin situ SAXS測定によるPEMの構造解析に成功した。

DOI： 10.1002/cssc.201301322

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We investigated the deleterious effects of the common practice of measuring cyclic voltammetry (CV) on Pt/CB catalysts during long-term start-up/shutdown cycling longevity evaluation of the type used in standard protocols used in the fuel cell automotive industry. These "interim" CV measurements, which are generally conducted after a certain number of potential cycles to evaluate the electrochemically active surface area (ECSA) of Pt catalysts, result in depassivation of the passive layer formed on Pt particles during the cycling tests; this allows the platinum to again catalyze the carbon corrosion effectively during the potential cycling. This phenomenon causes additional corrosion of the CB support. The measured ECSA loss, cycle half-life N-1/2 (N value at which the ECSA value was estimated to reach 1/2 of the initial value) and IR-free polarization curves show that the potential cycling, followed by intermittent CV measurements on the same electrode, termed consecutive cycling, brings about severe lifetime reduction and cell performance degradation of the Pt/CB catalyst. The quinone-hydroquinone (Q-HQ) oxidation current supports the idea that this degradation can be ascribed to severe corrosion of the CB support by the consecutive cycling. In addition, SEM and TEM images confirm that the interim CV measurements lead to severe degradation of the Pt/CB catalyst due to dissolution of platinum and carbon support corrosion. Thus, from the viewpoint of practical operation, the catalyst degradation is overestimated with this testing protocol. (C) 2014 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2013.12.120

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

We found that Nb-doped SnO2-delta nanoparticles were improved in their electrical conductivity by more than two orders of magnitude by the aggregation of the particles, including the fusion of nearest-neighbor particles to form a random branching structure, and the formation of a porous agglomerated structure similar to that of conventional carbon blacks. The electrical conductivity was increased by an additional two orders of magnitude as a result of the loading of Pt nanoparticles to produce an electrocatalyst (Pt/Nb-doped SnO2-delta) for fuel cell applications. We also found that the specific activities of Pt/Sn0.96Nb0.04O2-delta (16 wt% Pt loading) for the oxygen reduction reaction increased with increasing electrical conductivity of the support and exceeded that of a conventional Pt catalyst supported on carbon black (Pt/CB). Since the tin oxide supports are much more stable than CB supports to the exposure to positive potentials (0.9 similar to 1.3 V) during the start/stop operation of fuel cells, Pt or Pt alloy catalysts supported on oxide supports with such a chain-like, necked structure, as developed in this work, become superior candidates as robust cathode catalysts for the fuel cell vehicle application.

DOI： 10.1039/c4ra03988b

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ROYAL SOC CHEMISTRY  

Within the framework of developing reversible solid oxide fuel cells/solid oxide electrolysis cells (SOFCs/SOECs), we have engaged in the design of high-performance electrodes. Facile production of hollow spherical particles of samaria-doped ceria (SDC) decorated with Ni-Co alloy catalysts (Ni100-xCox/SDC, X = 0-50 atom%), nanometers in size, was adopted. A distinctive microstructure was observed in the hydrogen electrode fabricated with this composite powder. The cobalt addition played a significant role in evolution of the microstructure and effectively enlarged the electrochemical reaction zone. Under SOFC/SOEC reversible operation, the optimal performance characterized by a comparatively low ohmic resistance and high electrocatalytic activity was achieved with the Ni80Co20/SDC composition. At 900 degrees C and an overpotential of 0.1 V, the current density reached remarkably high values of 0.18 and 0.37 A cm(-2) in SOFC and SOEC operation, respectively.

DOI： 10.1039/C3RA47089J

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

The effect on PEFC performance of a gas diffusion layer (GDL) with a hydrophilic layer (HL) between the microporous layer (MPL) and the carbon paper (CP) was investigated at high and low humidity at normal operating temperatures and at subfreezing temperatures. Scanning electron microscopic examination and micro-Raman spectroscopic examination were carried out on the three-layer structure (MPL, HL and CP). In addition, high magnification SEM images of the samples showed that the HL had smaller pores than the MPL of the HL-GDL. Thus, we consider that the capillary pressure in the pores of the HL was higher than that in the MPL of the HL-GDL, which suggests that the HL can absorb more water. The performances of cells using the GDL with or without a HL were compared. The cell using a GDL with a HL showed a higher performance than a cell with a conventional GDL in the high current density region at both high and low humidity. At high humidity, the HL can absorb generated water, improving water removal from the catalyst layer (CL) to the GDL, and inhibiting the stoppage of gas diffusion by condensed water in the CL. At low humidity, the HL enhanced the water retention in the MEA, inhibiting the decrease of proton conductivity of the electrolyte by dehydration. A cell using a GDL with a HL also showed superior performance during cold startup from -10 degrees C, due to water removal by the HL, inhibiting the blockage of gas diffusion by condensed or frozen water in the CL These results indicate that an HL placed between the MPL and the carbon paper of the GDL can improve the PEFC performance over a wide range of operating conditions, including high and low humidity at normal temperatures and cold startup from subfreezing temperatures. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2013.12.050

Web of Science

Language：Japanese   Publishing type：(MISC) Introduction and explanation (scientific journal)  

固体高分子形燃料電池の触媒層におけるPt削減と耐久性向上のため、Ptの担持方法、カーボンやセラミックス担体の開発の経緯と将来性を解説した

Language：Japanese   Publishing type：(MISC) Introduction and explanation (scientific journal)  

固体高分子形燃料電池用カソード用のPt担持カーボン、Pt担持セラミックス触媒の研究成果を解説した

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

In polymer electrolyte fuel cells, it is essential to minimize Pt loading, particularly at the cathode, without serious loss of performance. From this point of view, we will report an advanced concept for the design of high performance catalysts and membrane-electrode assemblies (MEAs): first, the evaluation of Pt particle distributions on both the interior and exterior walls of various types of carbon black (CB) particles used as supports with respect to the "effective surface (ES)"
second, control of both size and location of Pt particles by means of a new preparation method (nanocapsule method)
and finally, a new evaluation method for the properties of MEAs based on the Pt utilization (UPt), mass activity (MA), and effectiveness of Pt (EfPt), based on the ES concept. The amounts of Pt catalyst particles located in the CB nanopores were directly evaluated using the transmission electron microscopy, scanning electron microscopy and corresponding three-dimensional images. By use of the nanocapsule method and optimization of the ionomer, increased MA and EfPt values for the MEA were achieved. The improvement in the cathode performance can be attributed to the sharp particle-size distribution for Pt and the highly uniform dispersion on the exterior surface of graphitized carbon black (GCB) supports. © 2013 the Owner Societies.

DOI： 10.1039/c3cp51801a

Scopus

PubMed

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

We found high activity and durability for oxide-supported Pt catalysts for the oxygen reduction reaction (ORR). These catalysts were supported on Sn 0.96Nb0.04O2-δ (Pt/Sn 0.96Nb0.04O2-δ
BET area of support, 37 m2 g-1
Pt loading, 10.0 wt%) and Sn0.96Sb 0.04O2-δ (Pt/Sn0.96Sb 0.04O2-δ
BET area of support, 33 m2 g-1
Pt loading, 12.3 wt%), by use of the rotating disk electrode (RDE) technique, and measured the I-E performance of single H2-air polymer electrolyte fuel cells (PEFCs) using these catalysts as the cathode. The nanoparticulate supports Sn0.96Nb0.04O 2-δ and Sn0.96Sb0.04O2-δ had an aggregated structure similar to that of carbon black (CB). The electrochemically active surface area of Pt, estimated by cyclic voltammetry measurements with the RDE, reached 79.7 m2 g-1 (Pt/Sn 0.96Nb0.04O2-δ) and 68.6 m2 g-1 (Pt/Sn0.96Sb0.04O2-δ). The ORR activity of Pt/Sn0.96Nb0.04O2-δ exceeded that of a commercialized Pt catalyst supported carbon black (Pt/CB). Higher durability was confirmed for Pt/Sn0.96Nb0.04O 2-δ and Pt/Sn0.96Sb0.04O 2-δ compared to that of Pt/CB with a test protocol for start/stop cycling recommended by the Fuel Cell Commercialization Conference of Japan (FCCJ) [1]. Single cells using these catalysts showed I-E performance superior to that for the Pt/CB at operating potentials above 0.4 V. For operating potentials below 0.4 V, a slight amount of Sn dissolution from the Sn0.96Sb0.04O2-δ support occurred, resulting in degradation of the cell performance due to Pt poisoning by Sn re-deposition, but no noticeable degradation at Sn0.96Nb 0.04O2-δ was found, due to the suppressed Sn dissolution. © 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2013.06.127

Scopus

Language：English   Publishing type：Research paper (scientific journal)  

PtTi合金の触媒活性と組成・粒子径との相関を明らかにした。

DOI： 10.1039/c3ta11499f

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

The corrosion of carbon black (CB) support materials for polymer electrolyte fuel cells was investigated by use of two standard accelerated testing protocols, square wave cycling (E = 0.9-1.3V vs. RHE, holding 30 s at each E) and triangular wave cycling (E = 1.0-1.5 V vs. RHE, at a can rate of 0.5 V s(-1)) protocols, which, were operated with H-2 (anode) and N-2 (cathode) atmospheres at 80 degrees C and 100% RH. Severe decreases of the electrochemically active surface area (ECSA), mass activity (MA(@0.85) (v)) and cell performance resulting from the simulated start-up/shutdown cycling are ascribed to the detachment of Pt particles from the CB support due to carbon corrosion and structural collapse, as well as Ostwald ripening. First, the simulated start-up/shutdown cycling brings about the surface corrosion of the CB particles, and thereafter it transforms the crystalline carbon into amorphous carbon, which subsequently undergoes corrosion. This continual corrosion process of the CB support leads to a significant thickness reduction of the Pt/CB cathode catalyst layer and the severe detachment of Pt particles from the CB. On the CB particles, the slower square wave cycling brings about their overall corrosion, including the surface defects and anchoring centers where Pt particles are well attached and dispersed, whereas the faster triangular wave cycling brings about corrosion locally at more unstable surface defects on the CB particles. This is why the estimated cycle half-life N-1/2 (at which ECSA is estimated to decrease to ca. 1/2 of the initial value) for the Pt/CB cathode catalyst was 10 times shorter with the square wave cycling compared to that with the triangular wave cycling. The effect of overall cycling time vs. cycle number is also discussed. (C) 2013 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2012.12.082

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Ptスキン層を有するPtCo合金触媒の合成に成功した。その触媒活性をチャンネルフロー二重電極法にて、微細構造をSTEM-EDXにて評価した。

DOI： 10.1021/am302224n

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

We synthesized Pt catalysts supported on titanium nitride nanoparticles (Pt/TiN. Pt loading, 8.9 wt%) by a colloidal method. The Pt nanoparticles were found to exhibit a characteristic hexahedral shape with clear faceting, with a lattice structure that was highly oriented to that of the TiN support, indicating a strong interaction between the Pt nanoparticles and the TiN support. We evaluated the electrochemical activity of the Pt/TiN both without and with mixing with electronically conducting acetylene black (AB), the latter denoted as Pt/TiN + AB. The electrochemically active surface area (ECSA) of Pt in Pt/TiN + AB was noticeably larger than that of Pt/TiN, reaching 108 m(2)g((pt))(-1) as a maximum, which was close to the geometrically estimated Pt surface area (127 m(2) g((pt))(-1)), based on transmission electron microscopy. By means of a potential step cycling test (0.9-1.3 V vs. RHE) simulating start/stop cycles in polymer electrolyte fuel cells (PEFCs), it was found that both of the TiN-based catalysts exhibited superior durability compared to commercial Pt catalysts supported on carbon black (Pt/CB) or graphitized carbon (Pt/GCB), based on the ECSA values. The mass activities at 0.85 V of both of the TiN-based catalysts for the oxygen reduction reaction (ORR) were also higher than those for commercial Pt/CB or Pt/GCB during the potential step cycling test. The superiority of the TiN catalysts must have arisen as a result of the stabilization of the Pt nanoparticles due to their strong interaction and well matched crystallographic structures, as well as the complete elimination of nanopores from the support surfaces. (C) 2012 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.electacta.2012.06.001

Web of Science

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：(MISC) Introduction and explanation (scientific journal)  

固体高分子形燃料電池のカソード用高耐久担体の設計とそのPt担持触媒の性能について解説した

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Ptを担持したSn0.96Sb0.04O2触媒を合成し、その酸素還元活性と起動停止サイクル耐久性を回転ディスク電極法にて明らかにした。

DOI： 10.1016/j.electacta.2010.12.077

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELECTROCHEMICAL SOC JAPAN  

We synthesized a Pt catalyst supported on nanometer-size titanium nitride particles (Pt/TiN) by the nanocapsule method. The titanium nitride (TiN) support, which was synthesized by the radio-frequency (RF) plasma method, had high electrical conductivity, up to 850 S cm(-1) at room temperature, with a surface area of 40 m(2) g(-1). The Pt loading on the catalyst was 19.5 wt%. The electrochemically active surface area (ECA) was 72 m(2) g(p)(-1). During the potential step cycling test (0.9 similar to 4.3 V), the ECA values for Pt/TiN remained high and exceeded that of a commercial Pt catalyst supported on carbon black (Pt/CB) for potential step cycle numbers above 300. From the results of linear sweep voltammetry using a rotating disk electrode, we observed that the oxygen reduction reaction activity of the Pt/TiN exceeded that of Pt/CB. We conclude that the nanometer-size TiN might be a good candidate support material for the cathode of the polymer electrolyte fuel cell (PEFC).

DOI： 10.5796/electrochemistry.79.399

Web of Science

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Aiming at SOFC anode applications, we have synthesized nanometer-sized nickel catalysts supported on hollow spherical particles of samaria-doped ceria (Ni/SDC) by spraying a mixed solution of nickel, samarium, and cerium nitrates into an atmospheric pressure plasma. The as-prepared particles consisted of SDC (average diameter d(SDC) = ca. 0.8 mu m) and uniformly dispersed nanometer-sized NiO particles. When reduced in H(2) at 800 degrees C or 1000 degrees C. Ni nanoparticles (average diameter d(Ni) = 34 nm) were found to be embedded uniformly into the SDC surface. (C) 2009 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ssi.2009.04.005

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

We have investigated the crystal phase and oxide ion conductivity of (Ba0.3Sr0.2La0.5)(In1-xM x)O2.75 (M = Sc and Yb) systems as a function of dopant content and unit cell free volume. All peaks in the XRD diffraction patterns of these systems (x = 0.0 - 0.4) were found to be assignable to pure cubic symmetry. The lattice parameter of the Sc-doped system decreased monotonically with rising dopant content, while the Yb-doped one showed a monotonic increase. The oxide ion conductivity of these systems increased with a unit cell free volume. Above a volume of 2.43 × 10-2 nm3, the oxide ion conductivity decreased. The oxygen vacancy content of the systems was controlled to be constant over the whole compositional range, which suggests that the mobile oxygen content should also be constant over the whole range. Above a free volume of 2.43 × 10-2 nm3, a broad Raman mode emerged from 350 cm-1 to 400 cm-1, which might relate to the local distortion of oxygen octahedra. We conclude that the oxide ion mobility grows with increasing unit cell free volume up to a critical volume, and then the mobility is degraded by the local distortion of the oxygen octahedra. © 2009 The Ceramic Society of Japan.

DOI： 10.2109/jcersj2.117.529

Scopus

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.14723/tmrsj.33.1119

Language：English   Publishing type：Research paper (scientific journal)   Publisher：MRS-Japan  

新たなブラウンミラーライト構造としてBa2(M,M')2O5（M=Al,Ga等、M'=希土類等）を創製しその結晶構造を明らかにした。

DOI： 10.14723/tmrsj.33.1081

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society of Japan  

The frequency dependences of dielectric constant (εr,) for 8 mol% Y2O3 stabilized ZrO2 (8YSZ) with two kinds of electrodes, Pt and La06Ca04 MnO3 (LCM), were successfully explained by the superposition of both electrolyte-electrode interfacial polarizations and Debye-type polarizations due to dopant-vacancy associates. The different behaviors in the frequency dependence of εr for 8YSZ having the different electrodes were ascribed to the dopant-vacancy associates, (Yzr-Vo) and (Yzr-Vo-Yzr), which were very large for 8YSZ with Pt electrode, but almost disappeared for 8YSZ with LCM electrode. The frequency dependences of the ac conductivity (σac) were also explained by the relaxation phenomena of the dopant-vacancy associates, suggesting that the dispersion of σac can not be ascribed to grain boundary effect of electrolyte.

DOI： 10.5796/electrochemistry.76.734

Scopus

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

BaCe1-xYxO3系ペロブスカイト酸化物のプロトン伝導度と結晶構造等との相関を明らかにした。

DOI： 10.14723/tmrsj.33.1089

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN SOC APPLIED PHYSICS  

The relationship between electrical conduction and dielectric properties was investigated for the oxide-ion conductor Gd2Zr2O7 having a fluorite-type structure. Computer simulation clarified that the anomalously large dielectric constant (epsilon(r)') was successfully explained by the superposition of the Debye-type polarization and the electrolyte-electrode interfacial polarization. Two Debye-type relaxations were observed at 673 K and above. The lower-frequency relaxation was ascribed to the dopant-vacancy associate, (Gd-Ce'-V-O(center dot center dot)-Gd-Ce'), and the higher one to the long range migration of oxide ions oil the basis of the discussions of both the activation energies and the relaxation frequencies. The frequency dependences of both the ac conductivity (sigma(ac)) and the loss tangent (tan delta) were also successfully explained using the dielectric parameters of the Debye-type dopan-vacancy associates.

DOI： 10.1143/jjap.47.5521

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Here we report, for the first time, the synthesis of highly crystalline novel mesoporous carbon/nitrogen (C/N)-codoped TiO2 (MCNT) using ethylene diamine and carbon tetrachloride as the source for nitrogen and carbon, KIT-6 as the template, and titanium tetraisopropoxide as the TiO2 source. The obtained material has been unambiguously characterized by various sophisticated techniques. XRD and TEM analysis revealed that the MCNT material possesses highly crystalline 3D structure with a continuous network of mesoporous channels as well as structure corresponding to TiO 2. UV-DRS analysis indicated that light absorption shifted to lower energy and stronger absorption in the visible light region. XPS revealed that C and N were doped effectively and C or N dopants might be present in the chemical environment of Ti-O-N or Ti-O-C. It has been found that the material is highly crystalline and possesses high surface area, pore volume and uniform pore size distribution. Owing to its textural characteristics, it could be useful for various applications, such as photocatalysis, fuel cells, bulky biomolecule adsorption and nanotechnology. © World Scientific Publishing Company.

DOI： 10.1142/S1793292008001210

Scopus

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：JAPAN SOC APPLIED PHYSICS  

The dielectric properties of Yb-doped CeO2 (Ce1-xYbO2-delta) which is an oxide-ion conductor were investigated. Numerical analysis of the frequency dependences of dielectric constants (epsilon') and dielectric loss factors (epsilon '') revealed that the dielectric characteristics can be successfully explained by the superimposition of both Debye-type polarization due to dopant-vacancy associates and electrolyte-electrode interfacial polarization. The temperature response of the dielectric properties was less active than that of the Sm- or Nd-doped CeO2 systems, which have higher oxide-ion conductivity than the present system. Three types of Debye-type polarizations were observed. The first polarization at the highest-frequency region was ascribed to a long-range migration of oxygen vacancies. The second and third polarizations at the lower-frequency region were ascribed to the dopant-vacancy associates. The observed values of sigma(ac) and tan delta were also successfully explained using the dielectric parameters that were obtained from the numerical analysis of dielectric constant.

DOI： 10.1143/JJAP.47.212

Web of Science

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

Frequency dependences of the dielectric constant (εr′ ) were investigated for the perovskite-type oxide BaCe0.9Y 0.1O3-δ, which is a typical proton conductor. Numerical calculation of the frequency dependence of εr′ clarified that the large εr′ originated from the superimposition of both electrolyte-electrode interfacial and Debye-type polarizations. The Debye-type polarizations which originated from the dopant-vacancy associates, (YCe′-Vo ..). were depressed under wet Ar atmosphere. Therefore, it can be speculated that the proton may occur according to the following equilibrium equation: H2O +Vo ..⇔2H . + Oo x.

DOI： 10.2109/jcersj2.116.350

Scopus

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Ln(2)Zr(2)O(7) (Ln = Yb, Y, Gd, Eu, Sm, Nd, La) system changed from fluorite (F)-type to pyrochlore (P)-type phases when the ionic radius ratios, r(Ln(3+))/r(Zr4+), were larger than 1.26. The oxide-ion conductivity showed sharp maximum at the vicinity of the phase boundary between the F- and P-type phases. The frequency dependence of dielectric constant (epsilon'(r)) and dielectric loss factor (epsilon ''(r)) were successfully explained by the superimposition of Debye-type polarization due to dopant-vacancy associate and electrode-electrolyte interfacial polarization by the numerical calculation. The peak of dielectric loss tangent (tan delta) was ascribed to the dopant-vacancy associate. The epsilon(r)(0) and dielectric constant of the associate (epsilon(r0)) showed also the maximum values at the vicinity of the phase boundary between the F- and P-type phases. (C) 2008 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.jpcs.2007.12.015

Web of Science

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

Frequency dependences of dielectric constant (ε′r) for 9 mol% Y2O3 doped ZrO2 (YSZ) single crystal which is a typical oxide-ion conductor was successfully explained by the superimposition of both electrolyte-electrode interfacial and Debye-type polarizations. Three kinds of Debye-type polarizations were observed at fairly high temperatures. The two polarizations were ascribed to defect associates, (Y′zr-V.. o)., which were observed in the tan δ spectra. The third polarization in the high frequency region was ascribed to a long range migration of oxygen vacancy, which was observed in the M″ spectra. The σac dispersion was also explained by the Debye-type polarizations.

DOI： 10.2109/jcersj2.115.546

Scopus

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Caを固溶させたCeO2における酸化物イオン伝導度について誘電緩和解析を行い酸素欠陥とドーパントとの会合メカニズムを明らかにするとともに、その移動をデバイモデルで説明した。

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Electrochemical Society of Japan  

The relationship between electrical conductivity and dielectric relaxation was investigated for 20 atom % Nd doped CeO2 (CeO 0.8Nd0.2O2-δ), which is a typical oxide-ion conductor. Computer simulation clarified that the anomaly large dielectric constant (εr) originated from the superimposition of both Debye-type polarization and interfacial polarization between electrolyte and electrode. Two kinds of the Debye-type relaxation appeared equal and above 773 K, which were ascribed to defect associates, (NdCe'-V O) and (Nd Ce x. The frequency dependence of ac conductivity (σac) was successfully explained by analyzing the dielectric loss factor (εr"). The σac values in high temperature and high frequency regions agreed with dc conductivity (σdc). The activation energy for σac agreed with that for high frequency Debye-type polarization.

DOI： 10.5796/electrochemistry.75.719

Scopus

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

Dielectric relaxations were investigated for the solid solution system Cc I Nd-1-x(x),O2-delta (0.0 <= x <= 0.5) having a fluorite-type structure, which is a typical oxide-ion conductor. The dielectric constants showed anomalously large values at low frequencies and high temperatures. Numerical analysis of frequency dependence of dielecti c constant (epsilon(')(r)) clarified that the anomalously large epsilon(')(r) originated from the superimposition of both Debye-type polarization and interfacial polarization between electrolyte and electrode. Two kinds of Debye-type relaxations observed were ascribed to defect associates, (Nd-Ce' - V-O'') and (Nd-Ce', - V-O-Nd-Ce' )(x). The Debye-type polarizations were also confirmed by analyzing the dielectric loss factor (c,epsilon(')(r)). When the oxide-ion conductivity decreased in the heavy Nd-doped samples, both the Debye-type and the interfacial polarizations also decreased, suggesting that ordering of oxygen vacancy suppressed the electric field response of Debye-type polarization, resulting in the decrease of oxide-ion conductivity. (c) 2007 Elsevier B.V.. All rights reserved.

DOI： 10.1016/j.ssi.2007.05.010

Web of Science

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The relationship between electrical conduction and dielectric relaxation was investigated for 20 at.% Sm doped CeO2 (Ce0.8Sm0.2O2-delta), which is a typical oxide-ion conductor. Numerical calculation clarified that the anomalously large dielectric constant (Et) originated from the superimposition of both Debye-type polarization and interfacial polarization between electrolyte and electrode. Two kinds of the Debye-type relaxation appeared at and above 673 K, which were assigned to defect associates, (Sm-Ce -Vo)center dot and (Sm-Ce')Vo-Sm-Ce)(x). The Debye-type polarization was also confirmed by analyzing the dielectric loss factor (epsilon(r)). Ac conductivity (sigma(ac)) in high temperature and high frequency regions agreed with do conductivity (sigma(dc)), while the dispersion of aa, was ascribed to the Debye-type polarizations. 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ssi.2007.04.013

Web of Science

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Ce1-xSmxO2系の酸化物イオン伝導度と誘電率との相関を明らかにしてドーパントと酸素欠陥との会合メカニズムをデバイモデルで明らかにした。

DOI： 10.2109/jcersj.115.264

Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCIENCE BV  

The relationship between oxide-ion conductivity and ordering of oxide ion in the (Y1-xLax)(2)(Ce1-xZrx)(2)O-7 system having a pyrochlore-type composition was investigated. The crystal phase of the system with a variable cation radius ratio, but with a constant lattice parameter, changed from a rare-earth-C (C)-type phase to a pyrochlore (P)-type phase through a fluorite (F)-type phase with increase in the composition (x), depending on the cation radius ratio r(A(3+))/r(B4+), which is a measure of ordering degree of oxygen vacancies. The oxide-ion conductivity increased once up to x = 0.15, and then decreased with increasing x. This change of the electrical conductivity was understood on the basis of the ordering degree of oxide ion. The Rietveld analyses of X-ray and neutron diffraction patterns, and Raman spectroscopy supported the ordering effect of oxide ion on the conductivity. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ssi.2006.12.013

Web of Science

Language：English   Publishing type：Research paper (scientific journal)  

Authorship：Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Ce0.9Sm0.1O2系酸化物のイオン伝導度と誘電率との相関を求め酸素欠陥とドーパントとの会合メカニズムをデバイモデルで明らかにしてイオン伝導メカニズムを解明した。

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

Perovskite-type oxyfluoride systems, ABO3-BaLiF3 (A = Ba, Ca and B = Ti, Zr) were investigated. In the Ba(Ti1-xLi x)O3(1-x)F3x system, cubic phases appeared in the range, 0.2≦x≦0.4. In the (Ca1-xBax) (Zr 1-xLix) O3(1-x)F3x system, orthorhombic phases different from CaZrO3 appeared in the range, 0.4 ≦x≦0.5. The lattice volumes of the new phases were larger than those of the respective end-members. On the other hand, the Ca1-xBa xTi1-xLixO3(1-x)F3x samples showed two phases of CaTiO3 and BaLiF3, of which lattice constants were almost independent of the composition.

DOI： 10.2109/jcersj.114.1160

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer  

The proton conductivity of (Ba1-x La (x) )(2)In2O5+x system has been investigated as a function of the La content, temperature and amount of absorbed water. The proton conductivity increased with La content up to x = 0.10, to reach a maximum of 1.12 x 10(-5) (S/cm) at 400 degrees C. From that point on, it decreased. From the results of thermogravimetry and mass spectra, we confirmed that the water was absorbed in the (Ba1-x La (x) )(2)In2O5+x system, in a maximum quantity of 0.14 mol/mol (sample). The proton conductivity increased monotonically with the quantity of water uptake, suggesting that this variable is one of the dominant parameter of proton conductivity in this system.

DOI： 10.1007/ｓ10853-006-0718-ｚ

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ssi.2006.06.023

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

DOI： 10.1016/j.ssi.2006.06.023

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramics Society of Japan  

BaxSryLa0.5InO2.5+y系酸化物における結晶内の陽イオン配置と電気伝導度との相関を解明した。

DOI： 10.2109/jcersj.114.399

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：ELSEVIER SCI LTD  

The electrical resistivity of the Zn1-x-yGaxInyO system was investigated as a function of the dopant content and mean dopant ion radius. The electrical resistivity of all members of the system exhibited metallic behavior as a function of temperature. The lowest electrical resistivity at 873 K fell to 2.81 x 10(-3) (Omega cm) in Zn0.99Ga0.0027O. In cases with the same dopant content, the resistivity strongly depended on the mean dopant ion radius, but the Seebeck coefficient was unrelated to those radii. Regardless of dopant content, the minimum resistivity of this system appeared around a mean dopant ion radius of 0.54 angstrom. Evidently, the carrier mobility is strongly dependent on the magnitude of the mean dopant ion radius and any structural distortion. (c) 2006 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

DOI： 10.1016/j.ceramint.2005.11.008

Web of Science

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

ZrO2膜の窒化による新たなZrN薄膜作製方法を確立した。

DOI： 10.2109/jcersj.113.458

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

We have conducted an electrical power generation experiment using a single cell of solid oxide fuel cell (SOFC) with (Ba0.3Sr0.2La0.5)InO2.75 as an electrolyte at an operating temperature of 800 degrees C. A moistened 10% hydrogen/argon mixture constituted the fuel gas, and air was the oxidant gas. As cathode and anode materials, we selected (La0.6Sr0.4)(Mn1-xFex)O3-delta (x=0-0.6) and Ni, respectively. The power density proved to be dependent on the Fe content of the cathode; use of (La0.6Sr0.4)(Mn0.6Fe0.4)O3-delta as a cathode material enabled us to reach a maximum power density of 0.58 W/cm(2). An analysis of X-ray Absorption Near-Edge Structure (XANES) taken to detect mixed valence of Mn and Fe showed that each valence was over 3.0. We also investigated, by X-ray diffraction and energy dispersive X-ray analysis (EDX), the diffusion of the constituent elements around the interface between the cathode and the electrolyte. Our results showed that the Mn, Fe and In diffused to the opposite phase. The interface resistance between electrolyte and electrode, which was measured by the direct current two-probe method, reached a minimum value at x=0.4, suggesting that the electronic conductivity of the interface would strongly affect the power generation. (c) 2005 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ssi.2005.04.048

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramic Society of Japan  

パイロクロア酸化物-蛍石構造の転移組成とドーパントイオン半径との相関を解明した。

DOI： 10.2109/jcersj.112.541

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Journal of Ceramic Society of Japan  

格子定数が同じYb2Ce2O7とNd2(Ce0.88Zr0.12)2O7を端成分とする(Yb1-xNdx)2(Ce1-0.88xZr0.88x)2O7の単位格子自由空間と電気伝導度との相関を明らかにした。

DOI： 10.2109/jcersj.113.236

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

A solid oxide fuel cell (SOFC) in which (Ba0.3Sr0.2La0.5)InO2.75 was used as an electrolyte was fabricated in order to characterize its
electrical power generation. Moistened 1% hydrogen gas balanced with argon gas was used as the fuel gas to prevent reduction of the
electrolyte. The chemical reaction between the electrolyte and some electrode materials has been investigated by X-ray diffraction. The
appropriate electrodes are Pt and Ni for the cathode and anode, respectively. The maximum power density was 0.51 (W/cm2) at 800 8C.

DOI： 10.1016/j.ssi.2004.09.030

Web of Science

Authorship：Last author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)  

固体電解質の新しい応用として酸化物イオン伝導体に直流電圧を印加してVOCの一つであるベンゼンの電気化学的分解を試みた。

DOI： 10.11451/mukimate2000.12.138

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramic Society of Japan  

Eu2Zr2O7及びLa2Ce2O7の交流伝導度を測定して酸化物イオン伝導度や粒界抵抗等の評価及び直流伝導度との相関を明らかにした。

DOI： 10.2109/jcersj.112.553

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Ceramic Society of Japan  

The thermal expansion and electrical resistivity for the perovskite oxide of (Ln1-xSrx)CoO3-δ(Ln = La, Nd and Sm) were measured as a function of temperature from room temperature to 1273 K in conditioned air. In the temperature range from room temperature to 1000 K, the thermal expansion coefficient was affected due to both the phase transition and change in the oxygen defect concentration. Moreover, above 1000 K, the Sr compositional dependency of the thermal expansion coefficient was quite similar to that of the electrical resistivity in all systems. In the high temperature range, all of the systems indicated the presence of metallic or semimetallic conduction, which was affected by lattice vibration. The thermal expansion also relies on lattice vibration, so that the thermal expansion coefficient at a high temperature would be linearly dependent on the electrical resistivity at the same temperature.

DOI： 10.2109/jcersj.112.342

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

Total electrical conductivity of (Ba0.5+xLa0.5-x) 2(In1-xMx)2O5.5 (M=Zr and Ce) and (Ba0.5-xLa0.5+x)2(In 1-xMx′)2O5.5 (M′=Mg, Ca and Sr) solid-solution systems was measured as functions of temperature and oxygen partial pressure. The oxide-ion conductivity of all the solid-solution systems increased at first with an increase in the unit cell free volume. However, it showed a maximum value at a unit cell free volume and then decreased. All the solid-solution systems showed a similar dependence of the oxide-ion conductivity on the unit cell free volume, even if they have different average ionic valences in the A- and B-sites. From the results of the Raman spectra measurement, the decrease of conductivity in the larger unit cell free volume range is presumed to arise from the local distortion of oxygen octahedra. © 2004 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.ssi.2003.12.025

Scopus

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：(MISC) Introduction and explanation (scientific journal)  

固体電解質材料の創製とその燃料電池への応用について解説した

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramics Society of Japan  

A2B2O7(A=Rare earth element,B=Zr,Ce)系酸化物における結晶構造と電気伝導度に関してAサイトとBサイトのイオン半径比との相関を解明した。

DOI： 10.14852/jcersjsuppl.112.0.S738.0

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：(MISC) Introduction and explanation (scientific journal)  

固体電解質材料の創製とその燃料電池への応用について解説した

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramics Society of Japan  

Ln2Ce2O7(Ln=La,Nd,Sm,Eu,Gd,Y,Yb)系における結晶系、酸化物イオン伝導度、自由空間体積とLnおよびCeとのイオン半径比との相関を明らかにした。

DOI： 10.2109/jcersj.111.902

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramics Society of Japan  

Ce0.8(A1-xBx)0.2O1.8 (A=Y,Gd B=Nd,La)系における電気伝導度とドーパントイオンの平均イオン半径比との相関を明らかにした。

DOI： 10.2109/jcersj.110.1021

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

The relationship between electrical conductivity and crystal structure was investigated for Ln2Zr2O7 (Ln=La, Nd, Sm, Eu, Gd, Y, or Yb) and (Ln1-xLn′x)2Zr2O7 (Ln=Gd, Sm, or Nd
Ln′=Y, Yb, or Gd) systems. The crystal structure of both systems changed from fluorite (F)-type to pyrochlore (P)-type structure when the ionic radius ratios, r(Ln3+)/r(Zr4+) or r(Lnav.3+)/r(Zr4+), were larger than 1.26, where r(Lnav.3+) is estimated from the ionic radius of the component ions and the composition using the following equation: r(Lnav.3+)=(1-x)r(Ln3+)+xr(Ln′3+ ). The lattice parameter increased linearly with increasing ionic radius ratios. The electrical conductivity at 800 °C in air for Ln2Zr2O7 systems showed the sharp maximum at the vicinity of the phase boundary between fluorite- and pyrochlore-type phases. The electrical conductivity of (Ln1-xLn′x)2Zr2O7 system also showed the maximum at the phase boundary for some combinations of Ln3+ and Ln′3+. The pyrochlore-type Eu2Zr2O7, which is located at the nearest position to the phase boundary, showed the highest conductivity of 8.3 × 10-3 S cm-1 at 800 °C. On the other hand, the activation energy for the conduction remarkably decreased with the increasing ionic radius ratios in the fluorite-type phase range and showed the minimum at the given compositions, at which the maximum electrical conductivities were observed and then increased. © 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0167-2738(02)00874-3

Scopus

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：Research paper (scientific journal)   Publisher：Kluwer Academic Publishers  

The conductivities of the Zn1-x-yMxM′yO (M, M′ = Al, In, Ga, Y) and Zn1-xMxO (M = Al, In, Ga) systems were measured from room temperature to 1173 K in order to elucidate a dominant parameter of the conducting mechanism. The conductivity at 873 K first increased with the dopant content. However, it showed a maximum value at a given dopant content, and then gradually decreased. For the samples with the same dopant content, their conductivity at 873 K was strongly dependent on the mean dopant-ion radii, and reached a maximum value at around 0.51 Å of the mean dopant-ion radii. The results suggested that the conductivity of the system would be influenced not only by the dopant content, but also by the mean dopant-ion radii. It was found that the co-doped ZnO system of Zn0.995Al0.003In0.003O had a conductivity higher than that of the other usual mono-doped system.

DOI： 10.1023/A:1021145312108

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

(Ba0.5-xSrxLa0.5)(In1–yMy)2O5.5(M=Y or Ga)系酸化物における酸化物イオン伝導度と組成、単位格子自由空間との相関を明らかにした。

DOI： 10.1023/A:1020616324734

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

The electrical conductivity of the LaY1-xInxO3 (x=0.0-0.7) system has been studied from the viewpoint of crystal chemistry. The high temperature form of LaYO3 (x=0.0) was ascertained to be the Sm2O3-type (B-type rare earth) structure, not perovskite-type one. The X-ray diffraction (XRD) experiments revealed that the samples with x=0.05 and 0.10 were the mixed phase of Sm2O3-type and perovskite-type structure, and changed to perovskite phase in the range of x≧0.20. From oxygen partial pressure dependence of the electrical conductivity, it was found that both the Sm2O3-type and the perovskite-type single phases showed hole conduction, but the mixed phase did oxide-ion one. The electrical conductivity of the LaY1-xIn(x)O3 (x=0.0-0.7) system increased with increasing x, and showed the maximum value in the range of x=0.05-0.10, and then decreased with increasing x. The occurrence of oxide-ion conduction was discussed from the viewpoint of lattice distortion in the mixed phase. © 2002 Elsevier Science B.V. All rights reserved.

DOI： 10.1016/S0167-2738(02)00521-0

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

DOI： doi.org/10.1016/S0167-2738(02)00495-2

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Kluwer Academic Publishers  

Electrical conductivity of the fluorite-type solid-solution system Zr0.7(Sc1-xMx)0.3O 2-δ (M = Ca, Mg, Al, Gd, Yb) was systematically investigated from the viewpoint of a stabilization effect of the cubic phase. The rhombohedral phase of Zr0.7Sc0.3O1.85 transformed to the cubic phase by the partial substitution of M for Sc. At the same time, the electrical conductivity abruptly increased. The electrical conductivity of the cubic phase decreased linearly and gradually with increase in oxygen vacancy content, but nevertheless the kind of dopants, and the extrapolated value of the conductivity to δ = 0.25 agreed with that of a pyrochlore-type La2Zr2O7. This fact was understood by considering that the partial substitution of M ions in place of Sc produced a micro-cluster having a pyrochlore-type structure with cubic symmetry. © 2002 Kluwer Academic Publishers.

DOI： 10.1023/A:1013643305260

Scopus

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramics Society of Japan  

Fine powders of In2O3 were obtained by thermal decomposition of the precipitates, which were prepared by an oxalate method in ethanol solution. The sinterability of the powders was improved considerably, compared with that of commercial powders. The maximum density reached 82% of the theoretical value by sintering at 1450 degreesC. Furthermore, the relative density increased as high as 90.9% by a new two-step sintering process, which includes a presintering step at a relatively low temperature and a final sintering step at 1450 degreesC under atmospheric condition. The electrical resistivity of sintered In2O3 was strongly dependent on the relative density and increased in proportion to the measurement temperature, showing metallic conduction behavior. The temperature coefficient (alpha) in the linear relationship was ascribed to an electron scattering effect due to porosities. The residual resistivity (rho (r)) of 0.0038 Omega (.) cm, which was estimated by extrapolation to 0 K, agreed with the value reported for the single crystal grown from vapor phase.

DOI： 10.2109/jcersj.109.1276_1000

Web of Science

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Ceramics Society of Japan  

Diffraction-line broadening was observed in the X-ray diffraction (XRD) profiles for samples sintered in a relatively short period in the perovskite-type solid-solution systems, Ba(Zn1/3Ta2/3)(1-x)MxO3-delta (M=Y, In, Ga), and it decreased with prolonged sintering period. The line broadening was ascribed to a fluctuation of lattice spacing (Deltad/d) that originated from structural imperfections due to ionic displacement, based on a beta cos theta vs sin theta plot. Furthermore, as a characteristic tendency, when a larger dopant ion substituted for the (Zn1/3Ta2/3) site in the solid-solution systems, a larger initial value of Deltad/d was observed which also decreased upon prolonged sintering. Electrical conductivity was strongly dependent upon Deltad/d. The relationship between electrical conductivity and Deltad/d was discussed from the viewpoint of disordering of the oxide ion.

DOI： 10.2109/jcersj.109.1272_656

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

(Ba1-xLax)2In2O5+x, whose end member is Ba2In2O5, is an oxygen-deficient perovskite oxide showing high oxide-ion conductivity. In order to clarify the reason why the high oxide ion conductivity appeared in this system, the electrical conductivity was measured as a function of temperature and La content. With an increasing La content, the discontinuous jump of ion conductivity in the Arrhenius plot, which is related to the disordering of the oxygen vacancies, disappeared for the sample with x≒0.2. Above x = 0.12, the ion conductivity linearly increased with La content, while the activation energy remained constant with respect to the La content. Moreover, the conductivity for x = 0.6 was 0.042 (S/cm) at 1073 K, which exceeded that of 8 mol% yttria-stabilized zirconia. The higher oxide-ion conductivity of this system could be dominated by the amount of mobile oxygen ions. © 2001 Elsevier Science B.V.

DOI： 10.1016/S0167-2738(01)00853-0

Scopus

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Electrochemical Society of Japan  

(Ce1-x-yLaxMy)O2(M=Ca, Sr)系における電気伝導度と組成との相関を明らかにした。

DOI： 10.5796/electrochemistry.68.455

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Springer  

新規酸化物イオン伝導体(Ba1–xLax)2In2O5+xの酸化物イオン伝導度と組成との相関を明らかにした。

DOI： 10.1023/A:1010117503009

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Materials Research Society of Japan  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Korean Physical Society  

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Korean Physical Society  

Pr1-xYxBa2Cu3Oy系酸化物の光学吸収スペクトルを測定し、電子構造を解明した。

Authorship：Lead author   Language：Japanese   Publishing type：(MISC) Introduction and explanation (bulletin of university, research institution)  

ペロブスカイト型酸化物の酸素欠陥と結晶構造・導電性について解説した

Authorship：Last author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：Korean Physical Society  

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：(MISC) Introduction and explanation (bulletin of university, research institution)  

ペロブスカイト型酸化物の酸素欠陥と結晶構造・導電性について解説した

Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Electrochemical Society of Japan  

(Ba,La)(In,M)O3系の電気伝導度と組成との相関を解明した。

DOI： 10.5796/electrochemistry.67.765

Language：English   Publishing type：Research paper (scientific journal)   Publisher：Elsevier  

(Y1-xMx)3NbO7(M=Ca,Mg)系及びYNb1-xMx3O7系の組成・結晶構造と電気伝導度との相関を解明した。

DOI： 10.1016/S0167-2738(99)00098-3

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：(MISC) Prompt report, short report, and research note, etc. (bulletin of university, research institution)  

高温超電導酸化物における格子欠陥と導電性との相関及び電子構造について解説した

Authorship：Lead author,　Corresponding author   Language：Japanese   Publishing type：(MISC) Prompt report, short report, and research note, etc. (bulletin of university, research institution)  

高温超電導酸化物における格子欠陥と導電性との相関及び電子構造について解説した

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Doctoral Thesis  

超電導酸化物、電子伝導酸化物の導電性と電子構造との関係を固体物理化学的見地をもとに導電率及び光学吸収スペクトルを駆使して解明した

Authorship：Lead author,　Last author,　Corresponding author   Language：Japanese   Publishing type：Doctoral Thesis  

超電導酸化物、電子伝導酸化物の導電性と電子構造との関係を固体物理化学的見地をもとに導電率及び光学吸収スペクトルを駆使して解明した

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：PERGAMON-ELSEVIER SCIENCE LTD  

Powder of BaPbxBiyOz with strictly controlled compositions were synthesized over a wide composition range of x and y. The region where the superconductivity appears to coincide with that of pseudo-cubic structure. In the superconducting phase, the oxygen content was found to exceed 3.00 suggesting that the excess oxygen plays an important role in realizing the superconductivity. (C) 1997 Elsevier Science Ltd.

DOI： 10.1016/S0038-1098(97)10077-1

Web of Science

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)   Publisher：American Institute of Physics Inc.  

We present measurements of the optical transmission and reflection performed at room temperature in the range from 0.2 to 3.5 eV on highly oriented PrBa2Cu3Oy films for oxygen contents between y=6.3 and 6.9. The spectra are discussed in terms of the absorption coefficient, determined directly from the measured transmission and reflection spectra. Three optical absorptions are resolved. For the oxygen content y=6.3, the absorption spectrum shows a gap of 1.1 eV, in good correspondence with the charge transfer gap of 1.21 eV determined from the high temperature conductivity. This energy gap decreases with oxygen content, but still exists for the oxygen content y=6.9. The electronic structure of the PrBa2Cu3Oy system is discussed within a semiconductor model in which the excess oxygen acts as an acceptor. © 1998 American Institute of Physics.

DOI： 10.1063/1.367203

Scopus

Authorship：Lead author,　Corresponding author   Language：English   Publishing type：Research paper (scientific journal)  

Pr1-xYxBa2Cu3Oy系酸化物の酸素欠陥量、電子伝導性を評価し、その電子構造を解析した。

DOI： 10.1103/PhysRevB.56.3494

Total pages：332   Language：Japanese   Book type：Scholarly book

燃料電池用ナノ粒子触媒の開発とその評価手法について解説した

Total pages：68   Responsible for pages：63   Language：Japanese   Book type：Scholarly book

Total pages：11   Responsible for pages：3   Language：Japanese   Book type：Scholarly book

Total pages：57   Responsible for pages：50   Language：Japanese   Book type：Scholarly book

固体高分子形燃料電池用カソード用のPt担持カーボン、Pt担持セラミックス触媒の研究成果を解説した

Total pages：9   Responsible for pages：3-11   Language：Japanese   Book type：Textbook, survey, introduction

Total pages：5   Responsible for pages：22-26   Language：Japanese   Book type：Scholarly book

Total pages：462   Responsible for pages：p.14-20   Language：Japanese   Book type：Dictionary, encyclopedia

セラミックスに関する基礎的な用語の解説

Total pages：215   Language：English   Book type：Scholarly book

Total pages：350   Language：English   Book type：Scholarly book

Total pages：558   Language：Japanese   Book type：Scholarly book

酸化物等の機能性材料の物性と格子欠陥との関係を解説した

Event date： 2024.3

Language：Japanese   Presentation type：Oral presentation(general)  

Venue：名古屋   Country：Japan  

Event date： 2023.12

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：London   Country：United Kingdom  

Event date： 2023.11

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：Tokyo   Country：Japan  

Event date： 2023.10

Language：English   Presentation type：Oral presentation(general)  

Venue：Gothenberg   Country：Sweden  

Event date： 2023.9

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Country：Japan  

Event date： 2023.8

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：web   Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：東京   Country：Japan  

Event date： 2023.5

Language：English   Presentation type：Oral presentation(general)  

Venue：Boston   Country：United States  

Event date： 2023.5

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：Tokyo   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation(general)  

Event date： 2023.3

Language：English   Presentation type：Symposium workshop panel(nominated)  

Venue：Kofu   Country：Japan  

Event date： 2022.10

Language：English   Presentation type：Oral presentation(general)  

Venue：Atlanta   Country：United States  

Event date： 2022.10

Language：English   Presentation type：Oral presentation(general)  

Venue：Atlanta   Country：United States  

Event date： 2022.10

Language：English   Presentation type：Oral presentation(general)  

Country：United States  

Event date： 2022.8

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：web   Country：Japan  

Event date： 2020.2

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

セラミックス担体を用いたPEFC用カソード触媒の性能（耐久性・活性）についてMEA及びRDEを用いた結果をもとに講演した。

Event date： 2019.12

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Language：Japanese   Presentation type：Oral presentation(invited, special)  

PEFCの高温作動時の性能、材料特性、劣化等を解説した。

Event date： 2019.12

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：東京  

第236回ECSにおける燃料電池関連発表内容をまとめると共にトピックを紹介した

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：東京  

第236回ECSにおける燃料電池関連発表内容をまとめると共にトピックを紹介した

Event date： 2019.11

Language：English   Presentation type：Oral presentation(invited, special)  

Language：English   Presentation type：Oral presentation(invited, special)  

セラミックス担体を用いたPEFC用触媒の性能・耐久性を講演した。

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：葉山  

セラミックス担体を用いたPEFC用触媒の性能・耐久性・合成方法等を講演した。

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation(general)  

Language：Japanese   Presentation type：Oral presentation(general)  

Venue：京都  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

固体高分子形燃料電池の基礎及び最新の研究動向を解説した。

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

固体高分子形燃料電池の基礎及び最新の研究動向を解説した。

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：Tokyo  

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：Tokyo  

燃料電池材料の最新の研究動向、評価技術及び課題等を解説した。

Event date： 2019.10

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

セラミックス担体を用いたPEFC用触媒の性能・耐久性・合成等を講演した。

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

セラミックス担体を用いたPEFC用触媒の性能・耐久性・合成等を講演した。

Event date： 2019.10

Language：English   Presentation type：Oral presentation(general)  

Venue：Atlanta, USA  

Language：English   Presentation type：Oral presentation(general)  

Venue：Atlanta, USA  

Event date： 2019.9

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

セラミックス担体を用いたPEFC用触媒を用いた単セルの性能・耐久性等を講演した。

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

セラミックス担体を用いたPEFC用触媒を用いた単セルの性能・耐久性等を講演した。

Event date： 2019.6

Language：Japanese   Presentation type：Symposium workshop panel(nominated)  

Venue：東京  

セラミックス担体を用いたPEFC用触媒の性能・耐久性・今後の研究方針等を講演した。

Language：Japanese   Presentation type：Symposium workshop panel(nominated)  

Venue：東京  

セラミックス担体を用いたPEFC用触媒の性能・耐久性・今後の研究方針等を講演した。

Event date： 2019.6

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

PEFCの高温作動における性能、劣化状態等に関する講演を行った。

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

PEFCの高温作動における性能、劣化状態等に関する講演を行った。

Event date： 2018.12

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：東京  

AiMES 2018(234th Electrochemical Society Meeting)での燃料電池関連の発表についてまとめると共にトピックを紹介した

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：東京  

AiMES 2018(234th Electrochemical Society Meeting)での燃料電池関連の発表についてまとめると共にトピックを紹介した

Event date： 2017.12

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

68th Annual Meeting of ISEにおける燃料電池関連の発表をまとめると共にトピックを紹介した

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

68th Annual Meeting of ISEにおける燃料電池関連の発表をまとめると共にトピックを紹介した

Event date： 2017.11

Language：English   Presentation type：Oral presentation(invited, special)  

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：Jeju,Korea  

Pt/セラミックス触媒の活性及びその燃料電池の性能に関して解説した

Event date： 2017.4

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：New Castle, England  

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：New Castle, England  

Pt担持セラミックス触媒の設計・合成・触媒活性、そして耐久性について解説した

Event date： 2017.2

Language：English   Presentation type：Oral presentation(invited, special)  

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：Bangkok,Thailand  

Pt担持セラミックス触媒の合成方法とその物性・触媒活性を解説した

Event date： 2016.6

Language：English   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：Boston, USA  

Language：English   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：Boston, USA  

Pt担持セラミックス触媒の設計・合成方法及び触媒活性と耐久性について解説した

Event date： 2013.7

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

燃料電池用Pt担持セラミックス触媒の設計・合成及び触媒活性について解説した

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東京  

燃料電池用Pt担持セラミックス触媒の設計・合成及び触媒活性について解説した

Event date： 2006.7

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：水戸  

ペロブスカイト酸化物(Ba1-x-ySrxLay)InO3の酸化物イオン伝導性等の物性及びそれを用いた固体酸化物形燃料電池の性能を解説した

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：水戸  

ペロブスカイト酸化物(Ba1-x-ySrxLay)InO3の酸化物イオン伝導性等の物性及びそれを用いた固体酸化物形燃料電池の性能を解説した

Event date： 2006.6

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東海  

ペロブスカイト型構造を有する新規固体電解質の物性と燃料電池への応用について解説した

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：東海  

ペロブスカイト型構造を有する新規固体電解質の物性と燃料電池への応用について解説した

Event date： 2005.4

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：taipei  

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：taipei  

新たな固体電解質の設計と物性を説明すると共に燃料電池への応用について解説した

Event date： 2005.3

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：熊本  

ペロブスカイト構造を有する新規高イオン伝導性酸化物の設計指針と物性及びその燃料電池への応用について解説した

Language：Japanese   Presentation type：Oral presentation(invited, special)  

Venue：熊本  

ペロブスカイト構造を有する新規高イオン伝導性酸化物の設計指針と物性及びその燃料電池への応用について解説した

Event date： 2004.10

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：Nara  

Language：English   Presentation type：Oral presentation(invited, special)  

Venue：Nara  

(Ba1-x-ySrxLay)InO2.5+y系酸化物の酸化物イオン伝導性、構造との相関について解説した

Event date： 2003.7

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：野田  

新規な固体電解質の設計指針とイオン伝導メカニズム及びその燃料電池への応用について解説した

Language：Japanese   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：野田  

新規な固体電解質の設計指針とイオン伝導メカニズム及びその燃料電池への応用について解説した

Event date： 2002.1

Language：English   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：Seoul  

Language：English   Presentation type：Public discourse, seminar, tutorial, course, lecture and others  

Venue：Seoul  

新規固体電解質の設計指針と物性及び燃料電池性能を解説した

Application no：特願2019-532533  Date applied：2018.7

Announcement no：WO2019/021904  Date announced：2019.1

Patent/Registration no：特許第7086338号 

Application no：特願2018-562443  Date applied：2018.1

Announcement no：WO2018/135611  Date announced：2018.7

Patent/Registration no：特許第7075562号  Date registered：2022.5 

Applicant：パナソニック

Application no：16811160.7  Date applied：2016.3

Patent/Registration no：3312921　（ドイツ特許番号：602016083708.0）  Date registered：2023.10 

Rights holder：新谷晴彦、柿沼克良、内田誠、渡辺政廣

Applicant：University of Yamanashi

Application no：特願2016-38455  Date applied：2016.2

Announcement no：特開2017-157353   Date announced：2017.9

Date published：2021.7

Patent/Registration no：特許第6919121号  Date registered：2021.7  Date issued：2021.8

Rights holder：柿沼克良、内田誠、飯山明裕

Application no：特願2015-166208  Date applied：2015.8

Announcement no：特開2016-047524  Date announced：2016.4

Patent/Registration no：特許第7190099号  Date registered：2019.11 

Application no：特願2015-159087  Date applied：2015.8

Announcement no：特開2017-037805  Date announced：2017.2

Patent/Registration no：6748953  Date registered：2020.8 

Country of applicant：Foreign country  

Application no：特願2015-121434  Date applied：2015.6

Announcement no：WO2016/020367  Date announced：2016.12

Patent/Registration no：第6150265号  Date registered：2018.6 

Country of applicant：Domestic  

Pt担持酸化物触媒の大気抵抗スイッチング機構を用いたカソード触媒の劣化抑制方法、およびそれを利用した高耐久燃料電池システムに関する特許

Application no：特願2016-511485  Date applied：2015.3

Announcement no：WO2015/151714  Date announced：2015.10

Patent/Registration no：特許第6173569号  Date registered：2017.7 

Country of applicant：Foreign country  

Pt担持酸化物触媒及び疎水性のカーボンの混合もしくはシリカ被覆による、ガス拡散性と撥水性を向上させた触媒層及び燃料電池関する特許

Application no：特願2015-540467  Date applied：2014.9

Announcement no：WO2015/050046  Date announced：2015.4

Patent/Registration no：特許第6471979号  Date registered：2019.2 

Country of applicant：Foreign country  

酸化スズ担体及び担持したPt触媒を相互反応させた高活性触媒及び燃料電池に関する特許

Application no：特願2014-060160  Date applied：2014.3

Announcement no：特開2014-112569  Date announced：2014.6

Patent/Registration no：第5858078号  Date registered：2015.12 

Country of applicant：Domestic  

噴霧熱分解法により合成した酸化物担体及びそのPt担持触媒に関する特許

Application no：特願2014-060159　  Date applied：2014.3

Announcement no：特開2014-146602  Date announced：2014.8

Patent/Registration no：特許第5858077号  Date registered：2015.12 

Country of applicant：Domestic  

ペロブスカイト構造を有する酸化物担体及びそれを用いた高活性なPt担持触媒に関する特許

Application no：特願2014-053222  Date applied：2014.3

Announcement no：特開2015-176794  Date announced：2015.10

Patent/Registration no：第6315180号  Date registered：2018.4 

Country of applicant：Domestic  

炭化物ナノ粒子による電極触媒担体、そのPt担持触媒及びそれらを用いた高性能な燃料電池に関する特許

Application no：特願2011-543315  Date applied：2010.11

Announcement no：WO2011/065471  Date announced：2011.6

Patent/Registration no：第5515019号  Date registered：2014.4 

Country of applicant：Foreign country  

耐久性、ガス拡散性と電子伝導性を触媒層内で両立させた連珠構造を有する酸化物もしくは窒　化物担体、その担体を用いた高活性・高耐久性を有するPt担持触媒、及びその触媒を用いた燃料電池に関する特許

Application no：特願2004-207622 

Announcement no：特開2006-27941  Date announced：2006.2

Patent/Registration no：特許第4501110号  Date registered：2010.4 

Country of applicant：Domestic  

酸化物薄膜から炭素による還元窒化を行う方法及びその窒化物に関する特許