NAGAI Takaaki


Institute of Advanced Sciences

Job Title

Specially Appointed Assistant Professor

Education 【 display / non-display

  • 1994.4

    Yokohama National University   Doctor Course   Completed

  • 1992.4

    Yokohama National University   Master Course   Completed

  • 1988.4

    Yokohama National University   Graduated

Degree 【 display / non-display

  • Doctor of Engineering - Yokohama National University

  • Master of Engineering - Yokohama National University

Campus Career 【 display / non-display

  • 2020.3

    Duty   Yokohama National UniversityInstitute of Advanced Sciences   Specially Appointed Assistant Professor  


Papers 【 display / non-display

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

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

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

    DOI Web of Science CiNii Research

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    Language:English   Publishing type:Research paper (scientific journal)   Publisher:公益社団法人 日本セラミックス協会   Joint Work  

    <p>Carbon-supported niobium oxide nanoparticle catalysts were synthesized for the oxygen reduction reaction (ORR) in acidic media. These catalysts were prepared using a <sup>60</sup>Co gamma-ray and heat-treated with polyacrylonitrile. Carbon black powder or multi-walled carbon nanotube (CNT) was used as the support for the niobium nanoparticle. Nb<sub>2</sub>O<sub>5</sub> nanoparticles with low crystallinity were fine and well dispersed on the carbon support in the as-irradiated samples. The loading amount of niobium increased with the absorbed dose, which indicated that niobium nanoparticles were produced by the irradiation. The as-irradiated composite nanoparticles were heat-treated under an H<sub>2</sub> atmosphere (5 %) or a mixed atmosphere of H<sub>2</sub> (2 %) and O<sub>2</sub> (0.05 %) to introduce active sites. The ORR activities were significantly enhanced by the heat treatment. Furthermore, the ORR activities were improved by using multi-walled CNT as the support.</p>

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

    Takeuchi Yuu, Matsuzawa Koichi, Nagai Takaaki, Ikegami Kaoru, Kuroda Yoshiyuki, Monden Ryuji, Ishih … Show more authors

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

    DOI Web of Science CiNii Research

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

    <p>Fe, N-doped SrTiO<sub>3</sub> was successfully synthesized using pyrazine carboxylic acid-metal complexes as the starting materials and exhibited high onset potential of 0.8 V vs. RHE for the oxygen reduction reaction because of the formation of high-quality active sites by Fe and N doping, and electron conduction paths by carbon nanotubes.</p>

  • Effect of Organic Ligands in Precursors on Oxygen Reduction Activity of Titanium-oxide Based Catalysts as Non-Platinum Cathodes for PEFCs

    Yuu Takeuchi, Koichi Matsuzawa, Keita Watanabe, Takaaki Nagai, Ryuji Monden, Akimitsu Ishihara

    22 ( 3 )   80 - 84   2023.1  [Reviewed]

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    Language:Japanese   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

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

    Electrochemistry   advpub ( 0 )   127001 - 127001   2023

    DOI Web of Science CiNii Research

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

    <p>We investigated the effect of adding Fe and F in the synthesis of zirconium-oxide-based cathode precursors to enhance the catalytic activity in the oxygen reduction reaction (ORR) in acidic media. In particular, we focused on adding F, and an ORR onset potential of 0.88 V was achieved by optimizing the amount of F added and heat treatment conditions contrary to a reversible hydrogen electrode. Additionally, a positive linear relationship was observed between the ORR onset potential and integrated intensity ratio of the monoclinic phase of ZrO<sub>2</sub> in the catalysts. This suggests that the monoclinic phase is fundamentally involved in the formation of active sites in the ORR in zirconium oxide-based cathodes.</p>

  • 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 Transactions   109 ( 9 )   389 - 399   2022.10  [Reviewed]

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

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Review Papers 【 display / non-display

  • 啓蒙普及の事例ー東京タワー・キッズ環境科学博士

    永井崇昭, 和田徹也

    燃料電池   17 ( 3 )   42 - 45   2018.1

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    Language:Japanese   Publishing type:Meeting report   Publisher:燃料電池開発情報センター   Joint Work  

  • 横浜国立大学グリーン水素研究センターの活動紹介と社会貢献

    太田健一郎, 石原顕光, 永井崇昭

    JETI   66 ( 1 )   121 - 125   2018.1

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    Language:Japanese   Publishing type:Rapid communication, short report, research note, etc. (bulletin of university, research institution)   Publisher:株式会社日本出版制作センター   Joint Work