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Observation of carrier dynamics in powder photocatalysts under magnetic field and its application

Research Project

Project/Area Number 20K15386
Research Category

Grant-in-Aid for Early-Career Scientists

Allocation TypeMulti-year Fund
Review Section Basic Section 36020:Energy-related chemistry
Research InstitutionOkayama University (2022)
Toyota Technological Institute (2020-2021)

Principal Investigator

KATO Kosaku  岡山大学, 自然科学研究科, 技術職員 (40751087)

Project Period (FY) 2020-04-01 – 2023-03-31
Project Status Completed (Fiscal Year 2022)
Budget Amount *help
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2020: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
Keywords光触媒 / キャリアダイナミクス / 過渡吸収 / 過渡吸収分光 / 磁場 / 磁場効果
Outline of Research at the Start

光触媒の活性を向上させるためには、光励起された電子と正孔の再結合を抑え寿命を延ばすことが重要である。近年、光触媒に磁場を印加すると光触媒活性が向上するという報告がなされ、磁場が電子と正孔のスピン状態を変化させ再結合を抑制するという機構が提案されている。本研究では磁場による光触媒活性向上のメカニズムの詳細を明らかにするため、過渡吸収分光法を用いて光触媒粉末中のキャリアダイナミクスを磁場下で実測する。また、助触媒の担持や不純物イオンのドープを行うことで、磁場による活性向上効果がさらに大きくなる条件を検討する。

Outline of Final Research Achievements

We studied photocarrier dynamics in photocatalysts using transient absorption spectroscopy. The experimental results suggested that defects on powder particle surfaces have dualistic properties of accelerating and decelerating electron-hole pair recombination, and which property becomes dominant is determined by the distribution of the defects. On the other hand, to investigate the origin of the previously reported effects of magnetic field on photocatalytic activities, we measured the photocarrier lifetime of photocatalysts under magnetic field. The sample was set in a cell between the gap of the electromagnet, and the transient absorption in the presence and absence of external magnetic field was compared. However, we could not find a significant effect of magnetic field on photocarrier lifetime, which suggests that magnetic field affects more strongly on the reactions of molecules after receiving photocarriers than on photocarrier dynamics inside photocatalysts.

Academic Significance and Societal Importance of the Research Achievements

光触媒を用いると,水と太陽光を用いてクリーンなエネルギー源である水素を生成したり,大気や水質の汚染物質を分解したりすることが可能で,様々な環境問題の解決策として近年大きく注目されている.本研究で過渡吸収分光測定を通して得られた新たな知見は,将来のより高活性な光触媒の開発において基礎となる,光触媒中における光励起キャリアのダイナミクスについての理解を深める上で有用であると考えられる.

Report

(4 results)
  • 2022 Annual Research Report   Final Research Report ( PDF )
  • 2021 Research-status Report
  • 2020 Research-status Report
  • Research Products

    (15 results)

All 2023 2022 2021 2020

All Journal Article (6 results) (of which Int'l Joint Research: 1 results,  Peer Reviewed: 6 results,  Open Access: 1 results) Presentation (9 results) (of which Int'l Joint Research: 1 results,  Invited: 1 results)

  • [Journal Article] Particle Size-Dependent Trap States of Photoexcited Carriers in Anatase TiO2 Nanoparticles2023

    • Author(s)
      Shimpei Naniwa, Kosaku Kato, Akira Yamamoto, Hisao Yoshida, Akira Yamakata
    • Journal Title

      The Journal of Physical Chemistry C

      Volume: 127 Issue: 8 Pages: 4295-4302

    • DOI

      10.1021/acs.jpcc.2c08125

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed
  • [Journal Article] Role of Oxygen Vacancy in the Photocarrier Dynamics of WO3 Photocatalysts: The Case of Recombination Centers2022

    • Author(s)
      Kato Kosaku、Uemura Yohei、Asakura Kiyotaka、Yamakata Akira
    • Journal Title

      The Journal of Physical Chemistry C

      Volume: 126 Issue: 22 Pages: 9257-9263

    • DOI

      10.1021/acs.jpcc.2c01662

    • Related Report
      2022 Annual Research Report
    • Peer Reviewed / Int'l Joint Research
  • [Journal Article] Forward and backward electron transfer on Pt loaded TiO2 photocatalysts under visible-light illumination2021

    • Author(s)
      Naohiro Inoue, Kyohei Shiraki, Kosaku Kato, Shu Ashimura, Masaaki Yoshida, Akira Yamakata
    • Journal Title

      Applied Physics Letters

      Volume: 119 Issue: 13 Pages: 133905-133905

    • DOI

      10.1063/5.0065074

    • Related Report
      2021 Research-status Report
    • Peer Reviewed
  • [Journal Article] Core-Shell Double Doping of Zn and Ca on β-Ga2O3 Photocatalysts for Remarkable Water Splitting2021

    • Author(s)
      Yamakata Akira、Vequizo Junie Jhon M.、Ogawa Takafumi、Kato Kosaku、Tsuboi Shoya、Furutani Naohiro、Ohtsuka Masahiro、Muto Shunsuke、Kuwabara Akihide、Sakata Yoshihisa
    • Journal Title

      ACS Catalysis

      Volume: 11 Issue: 4 Pages: 1911-1919

    • DOI

      10.1021/acscatal.0c05104

    • Related Report
      2020 Research-status Report
    • Peer Reviewed / Open Access
  • [Journal Article] Defect-Induced Acceleration and Deceleration of Photocarrier Recombination in SrTiO3 Powders2020

    • Author(s)
      Kosaku Kato and Akira Yamakata
    • Journal Title

      Journal of Physical Chemistry C

      Volume: 124 Issue: 20 Pages: 11057-11063

    • DOI

      10.1021/acs.jpcc.0c03369

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Journal Article] Enhancement of photoelectrochemical activity of TiO2 electrode by particulate/dense double-layer formation2020

    • Author(s)
      Hayashi Naruki、Kato Kosaku、Yamakata Akira
    • Journal Title

      The Journal of Chemical Physics

      Volume: 152 Issue: 24 Pages: 241101-241101

    • DOI

      10.1063/5.0010121

    • Related Report
      2020 Research-status Report
    • Peer Reviewed
  • [Presentation] 光触媒の磁場中キャリアダイナミクスの過渡吸収分光計測2022

    • Author(s)
      加藤康作,山方啓
    • Organizer
      日本化学会第102春季年会
    • Related Report
      2021 Research-status Report
  • [Presentation] 光触媒粉末のキャリアダイナミクスにおける欠陥の影響2021

    • Author(s)
      加藤康作,山方啓
    • Organizer
      2021年光化学討論会
    • Related Report
      2021 Research-status Report
  • [Presentation] WO3光触媒のキャリア再結合に対する酸素欠陥の影響2021

    • Author(s)
      加藤康作,上村洋平,朝倉清高,山方啓
    • Organizer
      第128回触媒討論会
    • Related Report
      2021 Research-status Report
  • [Presentation] 光機能材料における励起ダイナミクスの時間分解分光2021

    • Author(s)
      加藤康作, 山方啓
    • Organizer
      第15回物性科学領域横断研究会
    • Related Report
      2021 Research-status Report
  • [Presentation] Time-resolved spectroscopy of defect-induced effects on photocarrier dynamics in powder photocatalysts2021

    • Author(s)
      Kosaku Kato,Shoya Tsuboi,Akira Yamakata
    • Organizer
      Pacifichem2021
    • Related Report
      2021 Research-status Report
    • Int'l Joint Research
  • [Presentation] 広帯域過渡吸収分光法による光励起ダイナミクスの観測2021

    • Author(s)
      加藤康作
    • Organizer
      第2回動的エキシトン若手セミナー
    • Related Report
      2020 Research-status Report
    • Invited
  • [Presentation] 粉末欠陥における光励起キャリア緩和の初期過程2020

    • Author(s)
      加藤康作、山方啓
    • Organizer
      公益社団法人日本セラミックス協会第33回秋季シンポジウム
    • Related Report
      2020 Research-status Report
  • [Presentation] 粉末欠陥による光励起キャリアの再結合促進効果と抑制効果2020

    • Author(s)
      加藤康作、姜君哲、酒多喜久、山方啓
    • Organizer
      第126回触媒討論会
    • Related Report
      2020 Research-status Report
  • [Presentation] SrTiO3粉末の光励起キャリアダイナミクス2020

    • Author(s)
      加藤康作、姜君哲、酒多喜久、山方啓
    • Organizer
      第39回固体・表面光化学討論会
    • Related Report
      2020 Research-status Report

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Published: 2020-04-28   Modified: 2024-01-30  

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