Details of a Researcher - ISHIHARA Akimitsu

Papers - ISHIHARA Akimitsu

about 159

Effect of particle size on the oxygen reduction reaction activity of carbon‐supported niobium-oxide‐based nanoparticle catalysts

Naoki Shinyoshi, Satoshi Seino, Yuta Hasegawa, Yuta Uetake, Takaaki Nagai, Ryuji Monden, Akimitsu I … Show more authors

Journal of Materials Science 2025.2 [Reviewed]

DOI

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

Synthesis and characterization of zirconium oxide-based catalysts for the oxygen reduction reaction via the heat treatment of zirconium polyacrylate in an ammonia atmosphere

Atsuhiro Ueno, Satoshi Seino, Yushi Tamaki, Yuta Uetake, Takaaki Nagai, Ryuji Monden, Akimitsu Ishi … Show more authors

Journal of Materials Science 2025.1 [Reviewed]

DOI

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

Synthesis and characterization of titanium oxynitride catalyst via direct ammonia nitridation of titanium polyacrylate for oxygen reduction reaction

Yushi Tamaki, Satoshi Seino, Naoki Shinyoshi, Yuta Uetake, Takaaki Nagai, Ryuji Monden, Akimitsu Is … Show more authors

Journal of Materials Science: Materials in Engineering 19 40 2024.11 [Reviewed]

DOI

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

Improvement of ORR Activity of TiO2-Based Catalysts for PEFC Cathodes by Controlling Zn Addition Rate and Heat Treatment Atmosphere

Momo Obata, Koich Matsyzawa, Yuu Takeuchi, Takaaki Nagai, Ryuji Monden, Akimitsu Ishihara

The Journal of Fuel Cell Technology 24 ( 1 ) 58 - 65 2024.7 [Reviewed] [Invited]

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

Improvement of Oxygen Reduction Reaction Activity by Addition of Fe and Zn to Titanium Oxide-based Catalysts in Acid Electrolytes

23 ( 3 ) 83 - 94 2024.1 [Reviewed] [Invited]

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

Improvement of ORR Activity of Monoclinic Zirconium Oxides by Fe and F Co-addition for PEFC Cathodes

Yuu TAKEUCHI, Koichi MATSUZAWA, Yasuke MATSUOKA, Keita WATANABE, Takaaki NAGAI, Ryuji MONDEN, Akimi … Show more authors

Electrochemistry 91 ( 12 ) 127001 2023.11 [Reviewed]

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

Radiation-induced synthesis of carbon-supported niobium oxide nanoparticle catalysts and investigation of heat treatment conditions to improve the oxygen reduction reaction activity

Naoki Shinyoshi, Satoshi Seino, Yuta Uetake, Takaaki Nagai, Ryuji Monden, Akimitsu Ishihara and Tak … Show more authors

Journal of the Ceramic Society of Japan 131 ( 9 ) 575 - 580 2023.9 [Reviewed]

DOI

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

Electrochemical Characteristics of TiO2 Thin Films by Atomic Layer Deposition in Acidic Media and Their Applicability to Cathodes for PEFC

23 ( 1 ) 69 - 78 2023.7 [Reviewed] [Invited]

Authorship：Last author Language：Japanese Publishing type：Research paper (scientific journal) Single Work

Recent Advances in Nanocarbon-based Nonprecious Metal Catalysts for Oxygen/Hydrogen Reduction/Evolution Reactions and Zn-air Battery

Ganesan, Pandian; Ishihara, Akimitsu; Staykov, Alexander; Nakashima, Naotoshi

Bulletin of the Chemical Society of Japan 96 429 - 443 2023.4 [Reviewed] [Invited]

DOI

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

Structure and Electronic State Analyses of Interfaces in Metal Oxide Catalysts by Angle-Resolved-HAXPES

Matsumoto Masashi, Arao Masazumi, Ishihara Akimistu, Imai Hideto

SPring-8/SACLA Research Report 11 ( 1 ) 73 - 79 2023.2

DOI CiNii Research

Language：Japanese Publishing type：Research paper (scientific journal) Publisher：Japan Synchrotron Radiation Research Institute Joint Work

Fe, N-Doped SrTiO3 Synthesized Using Pyrazine Carboxylic AcidMetal Complexes: Application as an Oxygen Reduction Catalyst for Polymer Electrolyte Fuel Cell Cathodes in Acidic Media

Y. Takeuchi, K. Matsuzawa, T. Nagai, K. Ikegami, Y. Kuroda, R. Monden, and A. Ishihara

Bulletin of the Chemical Society of Japan 96 ( 2 ) 175 - 177 2023.2 [Reviewed]

DOI

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

固体高分子形燃料電池用非白金カソード触媒としてのチタン系酸化物触媒の酸素還元活性に前駆体有機配位子が与える影響

竹内悠、松澤幸一、渡辺啓太、永井崇昭、門田隆二、石原顕光

燃料電池 22 ( 3 ) 80 - 84 2023.1 [Reviewed]

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

Effects of Oxygen Defects in Zr Oxide-Based Thin Films on Oxygen Reduction Reaction in Acidic Media

Y. Watanabe, K. Matsuzawa, R. Monden, T. Nagai, and A. Ishihara

ECS Transaction 112 ( 4 ) 343 - 351 2023 [Reviewed]

DOI

Authorship：Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Single Work

Oxygen Evolution Activity on Mo Added Zr Oxide Catalyst in Alkaline Solution

Koichi Matsuzawa, Atsushi Nozaka, Kazuya Hirose and Akimitsu Ishihara

ECS Transaction 111 ( 4 ) 39 - 45 2023 [Reviewed]

DOI

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Single Work

Fe and Zn Addition Effects of Ti Oxide-Based Electrocatalyst on Catalytic Activity for Oxygen Reduction Reaction

Koichi Matsuzawa, Momo Obata, Yuu Takeuchi, Yoshiro Ohgi, Takaaki Nagai, Ryuji Monden and Akimitsu

ECS Transaction 111 ( 5 ) 29 - 34 2023 [Reviewed]

DOI

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Joint Work

In order to enhance the catalytic activity of non-precious oxide-based electrocatalyst for the oxygen evolution reaction (ORR), we have investigated the addition effects of Zn and Fe for Ti oxide-based electrocatalyst (TiOx) on the catalytic activity for the ORR. The Fe and Zn added TiOx (Fe,Zn-TiOx) was obviously the highest activity for the ORR, and it was higher ORR activity than Fe added TiOx (Fe-TiOx), Zn added TiOx (Zn-TiOx), and TiOx without addition. It reveals that the addition of Fe and Zn was found to be effective for enhancing the ORR activity, and Fe addition was more effective than Zn addition for enhancing the ORR activity on TiOx. As a result, it is suggested that Zn addition affected to increased electrochemical surface area of TiOx, and Fe addition affected to form active site in TiOx as similar case as Zr oxide-based electrocatalyst.

Effect of Iron Doping on Oxygen Reduction Activity of Zirconium Oxides Containing Carbon and Nitrogen Using Pyrazine Carboxylic Acid as Platinum Alternative Cathodes for PEFC

K. Watanabe, K. Matsuzawa, Y. Takeuchi, K. Ikegami, Y. Ohgi, T. Nagai, R. Monden, and A. Ishihara

ECS Transaction 109 ( 9 ) 389 - 399 2022.10 [Reviewed]

DOI

Authorship：Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Single Work

Analysis Method for Rotating Disk Voltammograms of Electrocatalytic Reaction —Oxygen Reduction Reaction—

Yuko YOKOYAMA , Takaaki NAGAI, Akimitsu ISHIHARA, Masahiro YAMAMOTO, Kohei MIYAZAKI, Takeshi ABE, … Show more authors

Electrochemistry 90 ( 10 ) 1030003 2022.8 [Reviewed]

DOI CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：公益社団法人　電気化学会 Single Work

Rotating disk voltammograms of electrocatalytic reactions were often analyzed on a model of the totally irreversible reaction. The problem with the conventional method is pointed out, and the validity of an analysis method on a model of the electrocatalytic reaction is demonstrated for oxygen-reduction reaction (ORR) as an example. Rotating disk voltammograms of ORRs sometimes show gradual change in the limiting current region called residual slope. The phenomenon has been explained on a random distribution model in which the catalytic sites communicate in long-range electron transfer with the electronic conductor that locate at distances (z), and are uniformly distributed with respect to z. Observed data of an ORR were well reproduced by non-linear least squares analysis on the random distribution model. The result of the analysis is briefly discussed.

Enhancement of Oxygen Reduction Activity of Fe-added Zirconium Oxide Electrocatalysts without Conductive Supports in Sulfuric Acid

Y. Takeuchi, K. Watanabe, K. Matsuzawa, T. Nagai, K. Ikegami, R. Monden, and A. Ishihara

Chemistry Letters 51 ( 9 ) 927 - 931 2022.8 [Reviewed]

DOI CiNii Research

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：公益社団法人日本化学会 Single Work

Fe-added zirconium oxide electrocatalyst was synthesized using pyrazine carboxylic acid for catalyzing oxygen reduction reactions (ORR) in acidic media. The optimization of the Fe-additive ratio led to the highest onset potential of 0.917 V for ORR at −10 mA gcat−1 compared to that of previous studies. The high ORR activity was due to the formation of high-quality active sites with Fe addition in monoclinic ZrO2 and a suitable electron supply path created through carbon deposited using a pyrazine carboxylic acid complex.

Effect of Foreign Elements Added Oxide-Based Electrocatalyst for Oxygen Reduction Reaction as Non-Precious Metal Cathodes

K. Matsuzawa, M. Obata, Y. Takeuchi, Y. Ohgi, K. Ikegami, T. Nagai, R. Monden, and A. Ishihara

ECS Transaction 108 ( 7 ) 181 - 188 2022.6 [Reviewed]

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Single Work

Applicability of P-doped SnO2 as an Oxide Support for PEFC Cathodes

21 ( 3 ) 79 - 88 2022 [Reviewed] [Invited]

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

Degradation Analysis of Pt/Nb–Ti4O7 as PEFC Cathode Catalysts with Controlled Arc Plasma-deposited Platinum Content

MA Yongbing, KAJIMA Hirokata, SHIMASAKI Yuta, NAGAI Takaaki, NAPPORN Teko W., WADA Hiroaki, KURODA … Show more authors

Electrochemistry 90 ( 5 ) 057004 2022 [Reviewed]

DOI CiNii Research

Language：English Publishing type：Research paper (scientific journal) Publisher：公益社団法人　電気化学会 Joint Work

For polymer electrolyte fuel cell cathodes, highly durable supports are required to prevent catalyst degradation in supports. In this study, as model Pt catalysts, 2–10 wt% Pt was deposited on Magnéli-phase niobium-doped macroporous Ti4O7 (Nb–Ti4O7) mounted on glassy carbon rods using the coaxial arc plasma deposition method. The morphologies of 2, 5, and 10 wt% Pt catalysts showed the hemisphere fine particles, islands with ca. 1.4 nm diameter and ca. 2.4 nm thickness, and films with ca. 3.3 nm thickness, respectively. During start/stop accelerated durability tests (ADTs) of 5000 cycles following the Fuel Cell Commercialization Conference of Japan protocol, Pt was slightly agglomerated; consequently, the morphologies of the 2, 5, and 10 wt% Pt catalysts were island-like with 3.5 nm thickness, chain bead-like with 4 nm thickness, and film-like with 4 nm thickness, respectively. This slight agglomeration led to good durability during the ADTs. Herein, the oxygen reduction reaction (ORR) mass activity (MA) values at 0.9 V vs. reversible hydrogen electrode (RHE) of the 2, 5, and 10 wt% Pt catalysts were 79, 60, and after 5000 cycles ADT, respectively, which had declining ratios after 5000 cycles were 32 %, 17 %, and 0 %, respectively. The island-like and film-like Pt/Nb–Ti4O7 presented activity and durability comparable to a Pt/C catalyst, which was (0.9 V vs. RHE) with a 12 % of declining ratio after the ADTs. The durability of the MA suggested that the different affinity caused by different crystal faces led to the slight agglomeration of 2, 5, and 10 wt%_Pt/Nb–Ti4O7 catalysts. These catalysts showed electrochemical surface areas (ECSAs) of 36, 27, and 29 m2 g−1 after the ADTs, with declining ratios as low as 20 %, 6 %, and 0 %, respectively. All Pt/Nb–Ti4O7 catalysts showed higher durability of the ECSAs than the Pt/C catalyst, which was 68 m2 g−1 with a 30 % declining ratio after the ADT. Different from common Pt nanoparticle catalysts, which agglomerate into large spherical Pt particles, the slight agglomeration was caused by the interconnection of the deposits and supplemented by a limited increase in the diameter or thickness. The island-like morphology of Pt with a limited thickness presented both high durability and activity among the Pt/Oxide catalysts.

Factors affecting ORR activity of Nb-added TiO2 catalysts supported on CNTs for PEFC

21 ( 1 ) 80 - 86 2021.7 [Reviewed]

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

Catalytic activity of zirconia on zirconium for the oxygen evolution reaction in potassium hydroxide

K. Matsuzawa, A. Ishihara, A. Oishi, S. Mitsushima, K. Ota

Materials Science and Engineering: B 267 115112 2021.3 [Reviewed]

DOI

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

It has been reported that the Ni anode electrode used in alkaline water electrolysis (AWE) is degraded when the fluctuating electricity produced by renewable energy (wind and solar power) systems is used. To develop alternative materials, we focused on zirconium oxide because of its high chemical stability, and investigated its catalytic activity for the oxygen evolution reaction (OER) on zirconium oxides on a zirconium plate fabricated by both air oxidation (ZrO2/Zr) and arc-plasma deposition (ZrO2/Zr_APD). From cross-sectional observations and electrochemical results, the mixed tetragonal and monoclinic structure of ZrO2 was related to its catalytic activity for the OER. ZrO2/Zr_APD showed obviously a higher activity than ZrO2/Zr. The reason for this is that the particles are better dispersed in ZrO2/Zr_APD than in ZrO2/Zr, so the electrochemical surface area of ZrO2/ Zr_APD seems to be larger than that of ZrO2/Zr.

Other Link： https://www.sciencedirect.com/science/article/pii/S0921510721000726?via%3Dihub

Control of surface area and conductivity of niobium-added titanium oxides as durable supports for cathode of polymer electrolyte fuel cells

Y.-B. Ma, T. Nagai, Y. Inoue, K. Ikegami, Y. Kuroda, K. Matsuzawa, Teko W. Napporn, Y. Liu, S. Mits … Show more authors

Materials and Design 203 109623 2021.3 [Reviewed]

DOI

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

Niobium-added titanium oxide is a promising candidate as a substitute carbon support for cathodes of PEFCs. Nb-added TiO2 can act as a support for platinum nanoparticles to enhance the oxygen reduction reaction (ORR) ac-tivity and durability under acidic conditions. Nb-added TiO2 supports with the desired surface area (10–130 m2 g−1) and conductivity (10−7–10−2 Scm−1) were prepared by changing the amount of Nb and the heat treatment conditions. First, we conducted a systematic investigation with changes in the amount of niobium addition, heat-treatment temperature, and time under a pure hydrogen atmosphere to reveal the physicochem-ical factors that govern the surface area and conductivity. Finally, we successfully proposed a procedure to pre-pare highly durable Nb-added TiO2 supports with the desired surface area and conductivity by controlling the amount of niobium addition, heat-treatment temperature, and time under hydrogen. The charges of the double layer were almost unchanged after 5000 cycles of an accelerated durability test (ADT).

Other Link： https://www.sciencedirect.com/science/article/pii/S0264127521001763?via%3Dihub

The Impact of Mn addition on Ta Oxide-Based Electrocatalysts for Oxygen Evolution Reaction in Acid

K. Matsuzawa, S. Hirayama, Y. Kohara, and A. Ishihara

ECS Transaction 104 ( 8 ) 431 - 436 2021 [Reviewed]

DOI

Authorship：Last author Language：English Publishing type：Research paper (international conference proceedings) Publisher：Electrochemical Society Joint Work

Noble Metal-Added Titanate Nanosheets for PEFC Cathode

Y. Takeuchi, K. Matsuzawa, T. Nagai, K. Ikegami, Y. Kuroda, R. Monden, and A. Ishihara

ECS Transaction 104 ( 8 ) 337 - 344 2021 [Reviewed]

DOI

Authorship：Last author,　Corresponding author Language：English Publishing type：Research paper (international conference proceedings) Publisher：Electrochemical Society Joint Work

Effect of Semiconducting Properties of Oxide-Based Compounds on Oxygen Reduction Activity in Acidic Media

A. Ishihara, J. Hirata, T. Nagai, Y. Kuroda, K. Matsuzawa, A. Imanishi, S. Mitsushima, Y. Takasu, a … Show more authors

ECS Transaction 98 ( 9 ) 457 - 464 2020.10 [Reviewed]

DOI

Language：English Publishing type：Research paper (international conference proceedings) Publisher：The Electrochemical Society Single Work

Effect of semiconducting properties of group 4 and 5 oxide-based films on catalytic activity of oxygen reduction reaction (ORR) has been investigated. In case of n-type semiconductor oxide catalysts, there are two reasons that the ORR activities are apparently observed to be low; one is that there are few active sites with high quality on the surface, another is that although the relative active sites are exists on the surface the Schottky barrier formed in the space charge layer of the oxides suppresses the electron transfer from bulk to the surface. The positive correlation between flat-band potential and onset potential for the ORR of thick oxide films composed of titanium-niobium, -tantalum, and -zirconium oxides was observed, indicating that the ORR activities were governed by the semiconducting properties of the films.

P-Doped SnO2 Powder as a Support for PEFC Cathode

Y. Inoue, K. Matsuzawa, Y. Ma, Y. Ohgi, T. Nagai, Y. Kuroda, S. Yamamoto, and A. Ishihara

ECS Transaction 98 ( 9 ) 565 - 572 2020.10 [Reviewed]

DOI

Language：English Publishing type：Research paper (international conference proceedings) Publisher：The Electrochemical Society Joint Work

A possibility of commercial P-doped SnO2 was evaluated as a non-carbon support for PEFC cathodes. The effect of heat-treatment under various conditions on the physical properties of the P-doped SnO2 was investigated. The P-doped SnO2 was sensitive by the heat-treatment in reductive atmosphere, 4%H2/Ar. The surface area was hardly affected by the heat-treatment in air or Ar even at high temperature such as 900 °C. On the other hand, the conductivity was dramatically affected by the atmosphere during the heat-treatment. The heat-treatment in Ar at higher temperature rather increased in the conductivity, whereas the heat-treatment in air caused the drastic decrease in the conductivity. This difference might be responsible for the formation and extinction of the oxygen vacancies.

Factors Affecting ORR Activity of Nb-Added TiOx Catalyst Using Carbon Support for PEFC

Y. Adachi, T. Nagai, Y. Ohgi, Y. Kuroda, K. Matsuzawa, S. Mitsushima, K. Ota, and A. Ishihara

ECS Transaction 98 ( 9 ) 555 - 563 2020.10 [Reviewed]

DOI

Language：English Publishing type：Research paper (international conference proceedings) Publisher：The Electrochemical Society Joint Work

Cup-stacked carbon nanotubes (CSCNTs) were covered with niobium-added titanium oxide by hydrolysis method to increase effective surface area of the oxides. In addition, reductive heat-treatment was performed to produce the active sites for the oxygen reduction reaction (ORR). The use of CSCNTs as supports was found to be effective to form the electron conductive path. The ORR currents of the Nb-added titanium oxide supported by CSCNTs significantly larger than those of Nb-added titanium oxide powder mixed with Ketjenblack. On the other hand, the ORR current at 0.6 V had maximum at the heat-treatment temperature of 800 °C. We focused on the ratio of Ti3+ of the catalysts and found that the positive correlation between the ratio of Ti3+ and the ORR current density at 0.6 V. Therefore, it was found that the formation of the oxygen vacancies on the oxide surface strongly affected the ORR activity.

Effect of Added Elements into TiO2 on Oxygen Reduction Activity in Acid Media

A. Ishihara, T. Nagai, M. Matsumoto, M. Arao, Y. Kuroda, K. Matsuzawa, H. Imai, S. Mitsushima, K. O … Show more authors

ECS Transaction 97 ( 7 ) 583 - 592 2020.8 [Reviewed]

DOI

Language：English Publishing type：Research paper (international conference proceedings) Joint Work

Challenge of advanced low temperature fuel cells based on high degree of freedom of group 4 and 5 metal oxides

Akimitsu Ishihara, Satoshi Tominaka, Shigenori Mitsushima, Hideto Imai4 Osamu Sugino and Ken-ichiro … Show more authors

Current Opinion in Electrochemistry 21 234 - 241 2020.3 [Reviewed] [Invited]

DOI

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

To obtain an ideal electrocatalysts for hydrogen fuel cells, we investigated group 4 and 5 oxide-based compounds because of their high degree of freedom. First-principles calculations revealed that oxide surfaces such as those of titanium oxide could break down the universal scaling to achieve the ideal state of the oxygen reduction reaction. We experimentally clarified that the active sites were oxygen vacancies for tantalum and zirconium oxides, in addition to doped foreign elements and crystalline structures for titanium oxide. We successfully demonstrated that precious metal-free and carbon-free oxide-based cathodes have high quality active sites and superior durability in 0.1 M sulfuric acid at 80oC. Our strategy was developed as follows: (1) Active sites are created on the oxide surface by modifying the crystalline structure and electronic states and (2) electrons participating in the oxygen reduction reaction are supplied by nanosized oxide particles and oxide films through the tunneling effect of electrons.

Other Link： https://www.sciencedirect.com/science/article/pii/S2451910320300624?via%3Dihub

Carbon Nanotube-Based Non-Precious Metal Electrode Catalysts for Fuel Cells, Water Splitting and Zinc-Air Batteries

Yang Jun, Ganesan Pandian, Ishihara Akimitsu, Nakashima Naotoshi

ChemCatChem 11 5929 - 5944 2019.12 [Reviewed] [Invited]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Publisher：Wiley-VCH Joint Work

Indium oxide supported Pt–In alloy nanocluster catalysts with enhanced catalytic performance toward oxygen reduction reaction

Yunlv Cheng, Xinshu Zhao, Yulv Yu, Lifang Chen, Tao Cheng, Jin Huang, Yan Liu, Masafumi, Harada, A … Show more authors

Journal of Power Sources ( 446 ) 227332 2019.11 [Reviewed]

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

Few currently applied carbon-supported metal cathode catalysts exhibit satisfactory durability under the harsh operation conditions of proton exchange membrane fuel cells. Herein we report for the first time a highly active In2O3 supported Pt–In alloy nanocluster (NC) catalyst (Pt–In/In2O3) toward oxygen reduction reaction, with small alloy NCs and a Pt content of 42 wt%, which exhibits obviously enhanced durability compared to currently applied carbon-supported Pt catalysts (Pt/C) and previously reported Pt NCs-based catalysts with a similar Pt content. The mass activity (MA) and specific activity (SA) over Pt–In/In2O3 are 0.32 A·mg−1Pt and 1.14 mA cm−2 at 0.9 V (vs. reversible hydrogen electrode (RHE)), respectively. Electron transfer from In to Pt in the alloy NCs occurs as confirmed by X-ray absorption measurements, which is an important cause of the high catalytic activity. After an accelerated aging test of 6000 potential cycles between 1.0 and 1.6 V, the MA loss over Pt–In/In2O3 is 3%, but that over Pt/C is 33%. The catalysts subjected to the aging test are characterized by transmission electron microscopy and X-ray diffraction to understand the extremely high durability.

Other Link： https://doi.org/10.1016/j.jpowsour.2019.227332

Titanium Oxide Nano-Particles as Supports of Cathode Catalysts for Polymer Electrolyte Fuel Cells

Y.-B. Ma, Y.-L. Cheng, Y. Inoue, T. Nagai, Y. Kuroda, K. Matsuzawa, S. Mitsushima, Y. Lib, Y. Wang … Show more authors

ECS Transaction 8 ( 92 ) 485 - 491 2019.10 [Reviewed]

DOI

Language：English Publishing type：Research paper (international conference proceedings) Publisher：The Electrochemical Society Joint Work

Because of low durability of carbon support which is widely used as a matrix of cathode catalyst in polymer electrolyte fuel cells (PEFCs), a novel carbon-free support with high durability is needed. The conductive oxide is one of the promising candidates due to its high durability. Titanium oxide nano-particles were already applied to an alternative material of carbon, with they have high chemical stability in the acid electrolyte and high electronic conductivity. In this study, we prepared a Nb-doped TiO2 by hydrothermal method and it was reduced in a pure hydrogen atmosphere to obtain Nb-TiOx support. Comparing with a commercial Pt/C catalyst, the Pt/Nb-TiOx catalyst behaved higher durability after 5000 cycles of start-stop accelerated durability test.

Effect of Nitrogen Doping on Oxygen Reduction Activity of TiO2 in Acidic Media

A. Ishihara, T. Nagai, N. Murase, M. Arao, Y. Kuroda, K. Matsuzawa, S. Mitsushima, K. Furukawa, H. … Show more authors

ECS Transaction 8 ( 92 ) 613 - 620 2019.10 [Reviewed]

DOI

Language：English Publishing type：Research paper (international conference proceedings) Publisher：The Electrochemical Society Joint Work

In order to investigate the effect of the nitridation of TiO2 on the ORR activity, TiO2 powders with three different kinds of crystalline structure (rutile, anatase, and brookite) were heat-
treated under NH3 containing gas atmosphere to dope the nitrogen. We found that the increase in the ORR activity by nitrogen doping depended on the crystalline structure of TiO2 and the apparent relationship was observed for rutile type TiO2. We found that the increase in the ORR activity of the rutile TiO2 with nitrogen content of 0.7wt% was responsible for the production of the oxygen vacancies in the rutile TiO2 as active sites and the formation of the electron supply path by formation of the electronic conductive Ti4O7 on the surface by nitridation.

Niobium-added titanium oxides powders as non-noble metal cathodes for polymer electrolyte fuel cells – Electrochemical evaluation and effect of added amount of niobium

Akimitsu Ishihara, Masazumi Arao, Masashi Matsumoto, Tsubasa Tokai, Takaaki Nagai, Yoshiyuki Kuroda … Show more authors

International Journal of Hydrogen Energy 2019.9 [Reviewed]

DOI

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

An appropriate evaluation of oxide-based compound powders as non-platinum cathodes for polymer electrolyte fuel cells is required to investigate the active sites of oxide-based cathodes for the oxygen reduction reaction. A mixture of carbon black powder as an electro-conductive material with oxide catalysts that had low electrical conductivity was attempted to evaluate the oxygen reduction reaction (ORR) activity. An appropriate mixture of carbon black and the oxide catalysts let to the electrochemical activation of the oxide surface by the formation of electron conduction networks. Using the carbon black mixture, the niobium-added titanium oxides heat-treated at 700 °C for 10 min under Ar containing 4% hydrogen without carbon materials were focused on to reveal the dependence of ORR activity on the added amount of niobium. The ORR activity of the niobium-added titanium oxides increased the Nb mole percentage from 0 to 20. This was due to the increase in the ratio of the Ti3+/(Ti4++Ti3+), and suggests that the active sites were Ti3+ and/or oxygen vacancies in the anatase phase. On the other hand, although the ratio of the Ti3+/(Ti4++Ti3+) of the oxide with an Nb mole percentage of 30 was almost twice as that with an Nb mole percentage of 20, the ORR activities were almost the same. This might be responsible for the deposition of the amorphous phase composed of Nb2O5, which consisted of a thin layer on the surface of the oxide particles and had low ORR activity.

Emergence of Oxygen Reduction Activity in Zirconium Oxide-Based Compounds in Acidic Media: Creation of Active Sites for Oxygen Reduction Reaction

Akimitsu Ishihara, Takaaki Nagai, Keisuke Ukita, Masazumi Arao, Masashi Matsumoto, Liwei Yu, Takah … Show more authors

Journal of Physical Chemistry C 123 18150 - 18159 2019.7 [Reviewed]

DOI

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

In order to develop zirconium oxide-based electrocatalysts for the oxygen reduction reaction (ORR), we attempted to clarify the factors that affect the ORR activity of oxide-based cathodes. We prepared zirconium oxide-based electrocatalysts from oxy-zirconium phthalocyanine with multi-walled carbon nanotubes as electroconductive supports via heat-treatment under a low oxygen partial pressure. We evaluated the density of the active sites, i.e., oxygen vacancies, using X-ray photon spectroscopy (XPS), the average particle size of the oxide particles using transmission electron microscope (TEM), and the surface area utilization of the oxide particles using TEM image analysis. We successfully determined that the increase in the ORR activity was due to the increase in the density of oxygen vacancies and the effective surface area, and that the decrease in the effective surface area was responsible for the decrease in the ORR activity.
In addition, we performed hard X-ray photoemission spectroscopy (HAXPES) analysis to understand the process by which the active sites were created. A comparison of the XPS and HAXPES results revealed that the oxygen vacancies were concentrated near the surface during heat-treatment under low oxygen partial pressure via the oxidation of the deposited carbon. The deposited carbon plays a role in creating ORR active oxygen-vacancy sites and promoting ORR by providing local nanoscale conduction paths on the relatively insulating oxide surfaces.

Templated Synthesis of Carbon-Free Mesoporous Magnéli-Phase Titanium Suboxide

Yoshiyuki Kuroda, Hikaru Igarashi, Takaaki Nagai, Teko W. Napporn, Koichi Matsuzawa, Shigenori Mits … Show more authors

Electrocatalysis 45 ( 10 ) 1 - 7 2019.6

DOI

Language：English Publishing type：Research paper (scientific journal) Publisher：Springer Joint Work

itanium suboxides, such as the Magnéli-phase TixO2x–1, have attracted much attention as candidates of stable electrode materials because of their high conductivity and stability. The synthesis of porous titanium suboxides with high surface area without the formation of residual carbon is important to achieve active and stable electrode materials. Here, the synthesis of mesoporous Magnéli-phase Ti6O11 without residual carbon is demonstrated for the first time by templating method, using a colloidal crystal template. Highly ordered mesoporous Magnéli-phase Ti6O11 was obtained by reduction of TiO2 framework within the template under H2 flow at 800 °C, followed by the removal of template with a sodium hydroxide solution. The BET surface area was 11 m2/g. The mesoporous Ti6O11 loaded with Pt nanoparticles deposited by the coaxial arc plasma deposition showed oxygen reduction reaction activity comparable to those of commercial Pt/C, though oxide support often reduces catalytic activity of supported Pt nanoparticles. Consequently, the mesoporous Ti6O11 is useful as a carbon-free electrochemical support material for various applications.

Other Link： https://link.springer.com/article/10.1007/s12678-019-00544-3

Oxygen Reduction Activity of TiO2 Single Crystals in Acidic Media

K.Ota, J. Hirata, T. Nagai, M. Arao, M. Matsumoto, Y. Kuroda, K. Matsuzawa, H. Imai, S. Mitsushima, … Show more authors

ECS Transaction 86 ( 13 ) 549 - 558 2018.10 [Reviewed]

Language：English Publishing type：Research paper (international conference proceedings) Publisher：The Electrochemical Society Joint Work

Factors affecting oxygen reduction activity of Nb2O5-doped TiO2 using carbon nanotubes as support in acidic solution

Akimitsu Ishihara, Chumeng Wu, Takaaki Nagai, Koji Ohara, Kengo Nakada, Koichi Matsuzawa, Teko Napp … Show more authors

Electrochimica Acta 283 1779 - 1788 2018.7 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER Joint Work

EFFECT OF NIOBIUM DOPING FOR ENHANCING ORR ACTIVITY OF NIOBIUM DOPED TITANIUM OXIDE ELECTRO-CATALYST

Chauhan Shipra, Arao Masazumi, Yogi Chihiro, Matsumoto Masashi, Imai Hideto, Tokai Tsubasa, Nagai T … Show more authors

グランド再生可能エネルギー国際会議論文集 1 ( 0 ) 2018.6

DOI

Language：English Publishing type：Research paper (scientific journal) Publisher：特定非営利活動法人再生可能エネルギー協議会 Joint Work

We performed the structure analysis of Nb doped titanium oxides oxygen reduction electro-catalysts in order to understand the effect of Nb doping on enhancing oxygen reduction reaction activity. Nb doping makes effects on stabilization of anatase phase of TiO2 with high ORR activity, lowering of particle size, and introduction and increment of Ti3+related to the ORR active sites. Large amount of Nb doping causes the suppression of ORR activity due to the covering of ORR active sites by non-active outer layers contain rutile, Ti4O7, and TiNb2O7 phases.

Other Link： https://ci.nii.ac.jp/naid/130007609913

Zirconium Oxide-Based Compounds as Non-Platinum Cathodes for Polymer Electrolyte Fuel Cells

K. Ota, T. Nagai, T. Miyazaki, M. Matsumoto, K. Matsuzawa, S. Mitsushima, H. Imai, and A. Ishihara

ECS Transaction 11 ( 77 ) 1465 - 1472 2017.10 [Reviewed]

DOI

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

Noncrystalline Titanium Oxide Catalysts for Electrochemical Oxygen Reduction Reactions

Satoshi Tominaka, Akimitsu Ishihara, Takaaki Nagai, and Ken-ichiro Ota

ACS Omega 2 ( 8 ) 5209 - 5214 2017.8 [Reviewed]

DOI Web of Science

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

Zirconium Oxynitride-Catalyzed Oxygen Reduction Reaction at Polymer Electrolyte Fuel Cell Cathodes

Mitsuharu Chisaka, Akimitsu Ishihara, Hiroyuki Morioka, Takaaki Nagai, Shihong Yin, Yoshiro Ohgi, K … Show more authors

ACS Omega 2 678 - 684 2017.2 [Reviewed]

DOI Web of Science

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

Temperature dependence of oxygen reduction mechanism on a titanium oxide-based catalyst made from oxy-titanium tetra-pyrazino-porphyrazine using carbon nano-tubes as support in acidic solution

T. Hayashi, A. Ishihara, T. Nagai, M. Arao, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. Ota

Electrochimica Acta ( 209 ) 1 - 6 2016.8 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER Joint Work

Titanium-niobium oxides mixed with Ti4O7 as precious-metal- and carbon-free cathodes for polymer electrolyte fuel cells

A. Ishihara, M. Hamazaki, M. Arao, M. Matsumoto, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. … Show more authors

J. Electrochem. Soc. 163 ( 7 ) F603 - F609 2016.7 [Reviewed]

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

Tantalum oxide-based electrocatalysts made from oxy-tantalum phthalocyanines as non-platinum cathode for polymer electrolyte fuel cell

N Uehara, A. Ishihara, M Matsumoto, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. Ota

Electrochim. Acta 2015.10

DOI Web of Science

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

Titanium-niobium oxides as non-precious metal cathodes for polymer electrolyte fuel cells

A. Ishihara, Y. Tamura, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. Ota

Catalysis 5 ( 3 ) 1289 - 1303 2015

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

Kinetic study of oxygen reduction reaction in acid solution on titanium oxide-based catalysts prepared from oxy-titanium tetra-pyrazino-porphyrazine

T. Hayashi, A. Ishihara, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. Ota

Electrochemistry 2015

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

Evaluation of durability of titanium-niobium oxides mixed with Ti4O7 as non-precious and carbon-free cathodes for PEFC in H2SO4 at 80oC

M. Hamazaki, A. Ishihara, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. Ota

Electrochemistry 2015

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

Nano-TaOxNy Particles Synthesized from Oxy-tantalum Phthalocyanine: How to Prepare Precursors to Enhance the Oxygen Reduction Reaction Activity after Ammonia Pyrolysis

M. Chisaka, A. Ishihara, N. Uehara, M. Matsumoto, H. Imai, K. Ota

J. Mater. Chem. A 3 16414 - 16418 2015

DOI Web of Science

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

Effect of Reheating Treatment on Oxygen-Reduction Activity and Stability of Zirconium Oxide-Based Electrocatalysts Prepared from Oxy-Zirconium Phthalocyanine for Polymer Electrolyte Fuel Cells

Y. Okada, A. Ishihara, M Matsumoto, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. Ota

J. Electrochem. Soc. 162 ( 9 ) F959 - F964 2015

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Publisher：ELECTROCHEMICAL SOC INC Joint Work

Synthesis of nano-TaOx oxygen reduction reaction catalysts on multi-walled carbon nanotubes connected via a decomposition of oxy-tantalum phthalocyanine

A. Ishihara, M. Chisaka, Y. Ohgi, K. Matsuzawa, S. Mitsushima and K. Ota

Phys. Chem. Chem. Phys. 17 ( 12 ) 7643 - 7647 2015

DOI Web of Science PubMed

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

Ti-Nb Oxide-based Catalysts as Non-platinum Cathodes for PEFC

15 ( 2 ) 79 - 86 2015 [Reviewed]

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

Kinetic study of oxygen reduction reaction on tantalum oxide-based electrocatalysts produced from oxy-tantalum phthalocyanines in acidic media

N Uehara, A. Ishihara, M Matsumoto, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, K. Ota

Electrochim. Acta 182 789 - 794 2015 [Reviewed]

DOI Web of Science

Language：English Publishing type：Research paper (scientific journal) Publisher：ELSEVIER Joint Work

Improvement of the Electrocatalytic Activity of Zirconium Oxide-based Catalyst for ORR

Y. Okada, A. Ishihara, M. Matsumoto, H. Imai, Y. Kohno, K.Matsuzawa, S. Mitsushima, K. Ota, M. Mats … Show more authors

ECS Trans. 64 ( 3 ) 231 - 238 2014 [Reviewed]

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

Oxide-based electrocatalysts as precious metal and arbon free cathodes for PEFC

M. Hamazaki, A. Ishihara, M. Arao, M. Matsumoto, H. Imai, Y. Kohno, K.Matsuzawa, S. Mitsushima, K. … Show more authors

ECS Trans. 64 ( 3 ) 239 - 246 2014 [Reviewed]

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

Enhancement of Oxygen Reduction Activity of Titanium Nano-Oxide-Based Electrocatalysts for PEFC Cathode

T. Hayashi, A. Ishihara, M. Matsumoto, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, and K. Ota

ECS Trans. 64 ( 3 ) 247 - 252 2014 [Reviewed]

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

PEFC 用非貴金属系カーボンフリー酸化物系触媒の開発

濱崎真, 石原顕光, 荒尾正純, 松本匡史, 今井英人, 河野雄次, 松澤幸一, 光島重徳, 太田健一郎

燃料電池 13 ( 3 ) 2014

Language：Japanese Publishing type：Research paper (other science council materials etc.) Joint Work

脱炭素を実現した世界初の非貴金属酸素還元触媒が、高い耐久性を持つことを明らかにした。

Factors which Affect Oxygen Reduction Activity of Zr Oxide-Based Electrocatalysts for PEFC

13 ( 3 ) 93 - 102 2014

Language：Japanese Publishing type：Research paper (other science council materials etc.) Joint Work

Determination of Oxygen-Reduction-Reaction Active Sites of Tantalum Oxide-based Cathodes Used for Polymer Electrolyte Fuel Cells

T. Asada, M. Arao, K. Kubobuchi, M. Mogi, Y. Takahashi, M. Matsumoto, A. Ishihara, K. Ota and H.Imai

Fuel Cells-from Fundamentals to Systems 14 ( 5 ) 769–774 2014

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

Immersed effects of Ta and Zr compounds on activity of oxygen reduction reaction in sulfuric acid

Matsuzawa Koichi, Nozawa Kazuhiro, Yamauchi Kyosuke, Ishihara Akimitsu, Mitsushima Shigenori, Ota K … Show more authors

JOURNAL OF POWER SOURCES 226 16 - 19 2013.3 [Reviewed]

DOI Web of Science

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

Factors for Improvements of Catalytic Activity of Zirconium Oxide-Based Oxygen-Reduction Electrocatalysts

Ohgi Yoshiro, Ishihara Akimitsu, Matsuzawa Koichi, Mitsushima Shigenori, Ota Ken-ichiro, Matsumoto … Show more authors

JOURNAL OF THE ELECTROCHEMICAL SOCIETY 160 ( 2 ) F162 - F167 2013 [Reviewed]

DOI Web of Science

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

Synthesis of carbon-supported titanium oxynitride nanoparticles as cathode catalyst for polymer electrolyte fuel cells

M. Chisaka, A. Ishihara, K. Ota, and H. Muramoto

Electrochim. Acta 113 735 - 740 2013

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Joint Work

Zirconium oxide-based cathode prepared by partial oxidation of carbonitrides as non-precious metal cathode for polymer electrolyte fuel cells

K. Ota, Y. Ohgi, K. Matsuzawa, S. Mitsushima, and A. Ishihara

ECS Trans. 53 ( 12 ) 1 - 8 2013 [Reviewed]

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

Improving ORR Activity of Group 4 and 5 Metal Oxide-Based Cathodes for PEFCs

A. Ishihara, S. Yin, K. Suito, N. Uehara, Y. Okada, Y. Kohno, K. Matsuzawa, S. Mitsushima, M. Chisa … Show more authors

ECS Trans. 58 ( 1 ) 1495 - 1500 2013 [Reviewed]

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

Activity of tantalum oxide-based electrocatalysts toward oxygen reduction reaction for PEFC

N. Uehara, A. Ishihara, Y. Kohno, K.Matsuzawa, S. Mitsushima, K. Ota

ECS Trans. 58 ( 1 ) 1217 - 1223 2013 [Reviewed]

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

Stabilization and activation of zirconium oxide based electrocatalysts as PEFC cathode by re-heat treatment

Y. Okada, A. Ishihara, M. Matsumoto, M. Arao, H. Imai, Y. Kohno, K.Matsuzawa, S. Mitsushima, K. Ota

ECS Trans. 58 ( 1 ) 1217 - 1223 2013 [Reviewed]

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

Enhancement of oxygen reduction activity of zirconium oxide-based cathode for PEFC

S. Yin, A. Ishihara, Y. Kohno, K.Matsuzawa, S. Mitsushima, K. Ota, M. Matsumoto, and H. Imai

ECS Trans. 58 ( 1 ) 1489 - 1494 2013 [Reviewed]

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

Nano-sized titanium oxides as electrocatalyst for oxygen reduction reaction toward PEFC

K. Suito, A. Ishihara, M. Matsumoto, M. Arao, Y. Kohno, K. Matsuzawa, H. Imai, S. Mitsushima, and K … Show more authors

ECS Trans. 58 ( 47 ) 1 - 7 2013 [Reviewed]

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

Factors for improvements of catalytic activity for zirconium oxide-based oxygen-reduction electrocatalysts

Y. Ohgi, A. Ishihara, K. Matsuzawa, S. Mitsushima, M. Matsumoto, H. Imai, and K. Ota

J. Electrochem. Soc. 160 ( 2 ) F162 - F167 2013

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：ELECTROCHEMICAL SOC INC Joint Work

Oxygen reduction reaction activity of nitrogen-doped titanium oxide in acid media

M. Chisaka, A. Ishihara, K. Suito, K. Ota, and H. Muramoto

Electrochim Acta 88 697 - 707 2013

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：ELSEVIER Joint Work

Highly Active Titanium Oxide-based Electrocatalyst for Oxygen Reduction Reaction for PEFC

12 ( 4 ) 130 - 137 2013

Language：Japanese Publishing type：Research paper (other science council materials etc.) Joint Work

Emergence of Oxygen Reduction Activity in Partially Oxidized Tantalum Carbonitrides: Roles of Deposited Carbon for Oxygen-Reduction-Reaction-Site Creation and Surface Electron Conduction

M. Chisaka, A. Ishihara, K. Ota, and H. Muramoto

J. Phys. Chem. C 117 ( 37 ) 18837 - 18844 2013

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：AMER CHEMICAL SOC Joint Work

Surface Reaction Analysis of Tantalum-Oxide Oxygen-Reduction Catalysts by Using X-ray Photoelectron Spectroscopy

M. Matsumoto, T. Miyazaki, S. Fujieda, A. Ishihara, K. Ota, and H. Imai

ECS Trans. 50 ( 2 ) 1759 - 1767 2012 [Reviewed]

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

Highly Active Titanium Oxide-based Catalyst for Oxygen Reduction Reaction for PEFC

K. Suito, A. Ishihara, M. Arao, M. Matsumoto, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, and K … Show more authors

ECS Trans. 50 ( 2 ) 1777 - 1783 2012 [Reviewed]

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

Preparation of Highly Active Zr Oxide-Based Oxygen Reduction Electrocatalysts as PEFC Cathode

S. Yin, A. Ishihara, Y. Kohno, K.Matsuzawa, S. Mitsushima, K. Ota, M. Matsumoto, M. Arao, and H. I … Show more authors

ECS Trans. 50 ( 2 ) 1785 - 1790 2012 [Reviewed]

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

Catalytic Activity and Stability of Ta Compounds for Oxygen Reduction Reaction

S. Mitsushima, Y. Fujita, A. Ishihara, Y. Ohgi, K. Matsuzawa, M. Matsumoto, M.i Arao, H. Imai, Y. K … Show more authors

ECS Trans. 50 ( 2 ) 1823 - 1829 2012 [Reviewed]

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

ORR Activity of Nb Oxide Based Catalyst Prepared from Nb Compound Including C and N

K.Hara, A. Ishihara, M. Matsumoto, M. Arao, H. Imai, Y. Kohno, K. Matsuzawa, S. Mitsushima, and K. … Show more authors

ECS Trans. 50 ( 2 ) 1769 - 1775 2012 [Reviewed]

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

Oxygen reduction reaction on tantalum oxide-based catalysts prepared from TaC and TaN

Y. Ohgi, A. Ishihara, K. Matsuzawa, S. Mitsushima, M. Matsumoto, H. Imai, and K. Ota

Electrochim Acta 68 192 - 197 2012

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：ELSEVIER Joint Work

Transition Metal Oxide Based Materials for Cathode of Polymer Electrolyte Fuel Cells

K. Ota, Y. Ohgi, K. Matsuzawa, S. Mitsushima, and A. Ishihara

ECS Trans. 45 ( 2 ) 27 - 33 2011 [Reviewed]

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

Pt-Ir-SnO2/C catalysts for ethanol oxidation in acidic media,

L. Zhao, S. Mitsushima, A. Ishihara, K. Matsuzawa, K. Ota

Chinese Journal of Catalysis 1856 - 1863 2011

Language：English Publishing type：Research paper (other science council materials etc.) Joint Work

Carbon nanowalls as platinum support for fuel cells

S. C. Shin, A. Yoshimura, T. Matsuo, M. Mori, M. Tanimura, A. Ishihara, K. Ota, and M. Tachibana

J. Appl. Phys. 110 ( 10 ) 104308 2011

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Joint Work

Catalytic Activity for Oxygen Reduction Reaction on Tantalum Oxide-Based Compounds (2) : Active Sites of TaON Thin Film Catalysts and Role of Carbon

75 ( 10 ) 552 - 556 2011

Language：Japanese Publishing type：Research paper (other science council materials etc.) Joint Work

Catalytic Activity for Oxygen Reduction Reaction on Tantalum Oxide-Based Compounds (1) : Effect of Preparation Conditions of Thin Film Model Catalysts Using Reactive Sputtering Method on Oxygen Reduction Activity

75 ( 10 ) 545 - 551 2011

Language：Japanese Publishing type：Research paper (other science council materials etc.) Joint Work

Quantitative Analysis of Electrooxidation Products on Platinum for Direct Ethanol Fuel Cell

K. Matsuzawa, T. Takahashi, A. Ishihara, S. Mitsushima, and K. Ota

Electrochemistry 79 ( 5 ) 419 - 423 2011

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：ELECTROCHEMICAL SOC JAPAN Joint Work

Zirconium oxide-based compounds as non-Pt cathode for polymer electrolyte fuel cell

K. Ukita, A. Ishihara, Y. Ohgi, K. Matsuzawa, S. Mitsushima, and K. Ota

Electrochemistry 79 ( 5 ) 340 - 342 2011

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：ELECTROCHEMICAL SOC JAPAN Joint Work

Ta oxide-based catalyst for PEFC

A. Ishihara, M. Tamura, K. Matsuzawa, S. Mitsushima, K. Ota

J. Fuel Cell Sci. Technol. 8 031005 2011

Language：English Publishing type：Research paper (other science council materials etc.) Joint Work

Development of Group 4 and 5 Metal Oxide-Based Cathodes for PEFC

K. Ota, Y. Ohgi, K-D. Nam, K. Matsuzawa, S. Mitsushima, A. Ishihara

Journal of Power Sources 196 ( 12 ) 5256 - 5263 2011

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：ELSEVIER Joint Work

Tantalum oxide-based compounds as new non-noble cathodes for polymer electrolyte fuel cell

A. Ishihara, K. Matsuzawa, S. Mitsushima, K. Ota, M. Matsumoto, H. Imai

Electrochimica Acta 55 ( 26 ) 7581–7589 2010.10

DOI Web of Science

Language：English Publishing type：Research paper (other science council materials etc.) Publisher：ELSEVIER Joint Work

Partially oxidized niobium carbonitride as a non-platinum catalyst for the reduction of oxygen in acidic medium

K-D. Nam, A. Ishihara, K. Matsuzawa, S. Mitsushima, K. Ota, M. Matsumoto, H. Imai

Electrochimica Acta 55 7290–7297 2010.9

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Papers - ISHIHARA Akimitsu