NAGASAWA Kensaku

Affiliation

Institute of Advanced Sciences

Job Title

Specially Appointed Associate Professor



Education 【 display / non-display

  • 2007.4
    -
    2010.3

    Yokohama National University   Doctor Course   Completed

  • 2007.4
    -
    2010.3

    Yokohama National University   Graduated

  • 2003.4
    -
    2005.3

    Yokohama National University   Master Course   Completed

Degree 【 display / non-display

  • Doctor of Engineering - Yokohama National University

  • Master of Engineering - Yokohama National University

Campus Career 【 display / non-display

  • 2020.4
     
     

    Duty   Yokohama National UniversityInstitute of Advanced Sciences   Specially Appointed Associate Professor  

  • 2017.7
    -
    2020.3

    Duty   Yokohama National UniversityInstitute of Advanced Sciences   Specially Appointed Assistant Professor  

  • 2016.11
    -
    2017.6

    Duty   Yokohama National UniversityFaculty of Engineering   Division of Materials Science and Chemical Engineering   Specially Appointed Assistant Professor  

 

Papers 【 display / non-display

  • A Novel Evaluation Method of Powder Electrocatalyst for Gas Evolution Reaction

    Nagasawa Kensaku, Matsuura Issei, Kuroda Yoshiyuki, Mitsushima Shigenori

    ELECTROCHEMISTRY   90 ( 1 )   017012 - 017012   2022

    DOI Web of Science CiNii Research

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

    <p>The evaluation of the powder catalyst activity is essential for the development of high-performance electrocatalysts for water electrolysis. However, the gas generated therein interferes with the accurate measurement by covering the catalyst surface. In this study, we have developed a new evaluation method for a powder oxide electrocatalyst using an alkaline electrolyte. This measurement and analysis method can obtain the intrinsic catalyst activity with no influence from the generation of bubbles. To establish this method, the electrolyzer for evaluation adopts the interdigit flow field for the <i>forced-flow method</i>, and the two methods, namely <i>time zero analysis</i> and <i>flow rate infinitization analysis</i>, were demonstrated by the extrapolation of the measurement data. As a result, the combination of <i>forced-flow method</i> and <i>time-zero analysis</i> is the best evaluation method for the determination of kinetic current at time zero as the equivalent of the no-generation gas condition.</p>

  • Corrosion-resistant non-noble metal electrodes for PEM-type water electrolyzer

    Tajuddin Aimi Asilah Haji, Elumalai Ganesan, Xi Zeyu, Hu Kailong, Jeong Samuel, Nagasawa Kensaku, F … Show more authors

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   46 ( 78 )   38603 - 38611   2021.11

    DOI Web of Science

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

  • Design and characterization of compact proton exchange membrane water electrolyzer for component evaluation test

    Nagasawa Kensaku, Ishida Taiki, Kashiwagi Hayato, Sano Yosuke, Mitsushima Shigenori

    INTERNATIONAL JOURNAL OF HYDROGEN ENERGY   46 ( 74 )   36619 - 36628   2021.10

    DOI Web of Science

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

  • A New Accelerated Durability Test Protocol for Water Oxidation Electrocatalysts of Renewable Energy Powered Alkaline Water Electrolyzers

    Abdel Haleem Ashraf, Nagasawa Kensaku, Kuroda Yoshiyuki, Nishiki Yoshinori, Zaenal Awaludin, Mitsus … Show more authors

    ELECTROCHEMISTRY   89 ( 2 )   186 - 191   2021  [Reviewed]

    DOI Web of Science CiNii Research

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

    <p>For electrocatalysts of oxygen evolution reaction (OER), a new accelerated durability test (ADT) protocol is presented. The protocol is designed to closely mimic the fluctuations of renewable energies. The unit cycle of the current ADT protocol represents the "ON/OFF" operation mode. In the "ON" step, the electrolyzer operates under a DC current of 0.6 A cm<sup>−2</sup>. In the "OFF" step, the electrocatalyst is subjected to a constant potential that is clearly more cathodic than its OER onset potential (namely, 0.3, 0.5, and 0.7 V vs. RHE) for 10 or 60 s. The transition from the "ON" state to the "OFF" state occurs through a cathodic linear sweep voltammetry of a fast sweep rate to mimic the sudden changes in the renewable power. A NiCoO<i><sub>x</sub></i>/Ni-mesh electrode was used as a case study. The electrode showed remarkable durability under continuous operation (<i>i</i> = 0.6 A cm<sup>−2</sup>) for about 900 hours. However, it did suffer severe degradation after a certain number of ADT cycles, and the rate of degradation mainly depends on the potential value and the duration of the "OFF" step. Interestingly, the inclusion of the 10-sec open-circuit potential step after the "ON" step clearly mitigates the impact of energy fluctuations on the durability of OER electrocatalysts.</p>

    Other Link: https://ci.nii.ac.jp/naid/130007995096

  • Current Measurement and Electrochemical Characterization of Gas Evolution Reactions on a Rotating Ring-Disk Electrode

    Bao Yun, Nagasawa Kensaku, Kuroda Yoshiyuki, Mitsushima Shigenori

    ELECTROCATALYSIS   11 ( 3 )   301 - 308   2020.5  [Reviewed]

    DOI Web of Science

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

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