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Characterization of Charge Separation in Visible Light-Sensitive TiO_2 by In-Situ ESR Spectroscopy

Research Project

Project/Area Number 17550178
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Inorganic industrial materials
Research InstitutionHiroshima University

Principal Investigator

KOMAGUCHI Kenji  Hiroshima University, Graduate School of Engineering, Assistant Professor (80291483)

Project Period (FY) 2005 – 2007
Project Status Completed (Fiscal Year 2007)
Budget Amount *help
¥3,770,000 (Direct Cost: ¥3,500,000、Indirect Cost: ¥270,000)
Fiscal Year 2007: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2006: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2005: ¥1,600,000 (Direct Cost: ¥1,600,000)
KeywordsTitanium dioxide / Electron spin resonance spectroscopy / Photosensitization / Photoinduced charge transfer reaction / 電荷移動錯体 / 可視光応答
Research Abstract

In-situ ESR studies were curried out to characterize paramagnetic species as the trapped electrons and notes generated and explore their transfer processes under visible light illumination in partially reduced TiO_2 and naphthol-adsorbed TiO_2 at 77 K.
1. For the partially reduced pure anatase and rutile particles, a broad singlet ESR spectra due to Ti^<3+> (trapped electron) decreased in intensity upon visible light illumination, and then restored to the initial intensity in the dark. For the TiO_2 (P25) particles, however, the signal restored up to 2.5-3 times greater than before. Through the analysis of the spectral line shape, it was found that the electrons are transferred from the anatase to the rutile particles by photoexcitation in reduced TiO_2(P25).
2. For O_2^- formed on partially reduced TiO_2 nanoparticles, the O2 and the surface Ti^<3+> signals were increased by 2-3 times upon illumination with visible light and reduced to the initial one by annealing the sample to r.t. in … More the dark. Assuming a reversible electron transfer reaction between Ti^<4+>-O_2^<2->-Ti^<4+> and Ti^<4+>-O_2^- + Ti^<3+>, the photoresponse was kinetically analyzed in terms of the trapping site of the O_2^- species.
3. For 1-naphthol-adsorbed TiO_2 in 2-propanol suspension, electrons were transferred from the charge-transfer complex of the naphthol bound to the TiO_2 surface to be trapped as inner Ti^<3+> under visible light illumination. The signal intensity of Ti^<3+> reflected the efficiency of the photosensitization, which depended significantly on the structure of adsorbed molecules and photon energies illuminated. The kinetic analysis of the photoresponse suggested that electron trapping as surface Ti^<3+> is involved in the interfacial charge transfer process.
The study demonstrated that ESR spectroscopy is useful in evaluating the charge-separation efficiency in visible light-sensitive TiO_2 and presented interesting and fundamentally important results for deepening understandings of the charge transfer processes. Less

Report

(4 results)
  • 2007 Annual Research Report   Final Research Report Summary
  • 2006 Annual Research Report
  • 2005 Annual Research Report
  • Research Products

    (27 results)

All 2008 2007 2006 2005

All Journal Article (4 results) (of which Peer Reviewed: 1 results) Presentation (23 results)

  • [Journal Article] High-Resolution ESR Study of the H…CH_3, H…CHD_2, D…CH_2D, and D…CD_3 Radical Pairs in Solid Argon2007

    • Author(s)
      K.Komaguchi, K.Nomura, M.Shiotani
    • Journal Title

      J. Chem. Phys. A 111・4

      Pages: 726-733

    • Related Report
      2006 Annual Research Report
  • [Journal Article] Photoinduced Electron Transfer from Anatase to Rutile in Partially Reduced TiO_2(P-25) Nanoparticles: An ESR Study2006

    • Author(s)
      K. Komaguchi
    • Journal Title

      Chem. Phys. Lett. 428・4-6

      Pages: 338-342

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
    • Peer Reviewed
  • [Journal Article] Photoinduced electron transfer from anatase to rutile in partially reduced TiO_2 (P-25) nanoparticles : An ESR study2006

    • Author(s)
      Kenji, Komaguchi, Haruka, Nakano, Atsunori, Araki, Yutaka, Harima
    • Journal Title

      Chem. Phys. Lett 428

      Pages: 338-342

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Journal Article] Photoinduced Electron Transfer from Anatase to Rutile in Partially Reduced TiO_2(P-25) Nanoparticles : An ESR Study2006

    • Author(s)
      K.Komaguchi, H.Nakano, A.Araki, Y.Harima
    • Journal Title

      Chem. Phys. Lett. 428・4-6

      Pages: 338-342

    • Related Report
      2006 Annual Research Report
  • [Presentation] ナフトールを吸着させたTiO_2の2-プロパノール懸濁液における光増感電子移動反応2008

    • Author(s)
      駒口健治
    • Organizer
      日本化学会第88春季年会
    • Place of Presentation
      東京
    • Year and Date
      2008-03-29
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Annual Research Report 2007 Final Research Report Summary
  • [Presentation] Photosensitized electron-transfer reactions in 2-propanol suspension of naphthol-adsorbed TiO_22008

    • Author(s)
      K., Komaguchi, S., Miura, T., Maruoka, Y., Ooyama, I., Imae, Y., Harima
    • Organizer
      The 88th Spring Meeting of the Chemical Society of Japan
    • Place of Presentation
      Tokyo
    • Year and Date
      2008-03-29
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] TiO_2表面に生成したO_2-ラジカルの可逆的光化学反応2008

    • Author(s)
      駒口健治
    • Organizer
      日本化学会第88春季年会
    • Place of Presentation
      東京
    • Year and Date
      2008-03-27
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Reversible Photochemical Reactions of O_2 on TiO_2 Surface2008

    • Author(s)
      K., Komaguchi, T., Maruoka, Y., Ooyama, I., Imae, Y., Harima
    • Organizer
      The 88th Spring Meeting of the Chemical Society of Japan
    • Place of Presentation
      Tokyo
    • Year and Date
      2008-03-27
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] TiO_2表面に生成したO_2^-ラジカルの可逆的光化学反応2008

    • Author(s)
      駒口健治
    • Organizer
      日本化学会第88春季年会
    • Place of Presentation
      東京
    • Year and Date
      2008-03-27
    • Related Report
      2007 Annual Research Report
  • [Presentation] 還元したTiO_2ナノ粒子に吸着したスーパーオキシドの光反応2007

    • Author(s)
      駒口健治
    • Organizer
      2007年日本化学会西日本大会
    • Place of Presentation
      岡山
    • Year and Date
      2007-11-11
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Annual Research Report 2007 Final Research Report Summary
  • [Presentation] Photochemical reactions of superoxide radical anions adsorbed on the surface of reduced TiO_2 nanoparticles2007

    • Author(s)
      T., Maruoka, K., Komaguchi, I., Imae, Y., Ooyama, Y., Harima
    • Organizer
      The 2007 West Japan Meeting of the Chemical Society of Japan
    • Place of Presentation
      Okayama
    • Year and Date
      2007-11-11
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Dual and reversible inter-conversion reactions of superoxide radical anion on TiO_2 under sub-bandgap illumination at 77 K2007

    • Author(s)
      Kenji Komaguchi
    • Organizer
      電子スピンサイエンス国際会議-第46回電子スピンサイエンス学会年会合同討論会
    • Place of Presentation
      静岡
    • Year and Date
      2007-11-07
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Annual Research Report 2007 Final Research Report Summary
  • [Presentation] Dual and reversible interconversion reactions of superoxide radical anions on TiO_2 under sub-bandgap illumination at 77 K2007

    • Author(s)
      K., Komaguchi, T., Maruoka, H., Nakano, I., Imae, Y., Ooyama, Y., Harima
    • Organizer
      A Joint Conference of the International Symposium on Electron Spin Science and the 46th Annual Meeting of the Society of Electron Spin Science and Technology (ISESS-SEST2007)
    • Place of Presentation
      Shizuoka
    • Year and Date
      2007-11-07
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 二酸化チタン表面におけるスーパーオキシドの光化学反応2007

    • Author(s)
      駒口健治
    • Organizer
      第11回ESRフォーラム研究会
    • Place of Presentation
      京都
    • Year and Date
      2007-06-09
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 色素モデル分子で修飾したTiO_2の光励起電荷分離特性2007

    • Author(s)
      駒口健治
    • Organizer
      第11回ESRフォーラム研究会
    • Place of Presentation
      京都
    • Year and Date
      2007-06-09
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Photochemical reaction of superoxides on the surface of titanium dioxides2007

    • Author(s)
      T., Maruoka, H., Nakano, K., Komaguchi, Y., Harima
    • Organizer
      The 11th Research Meeting of the ESR Forum
    • Place of Presentation
      Kyoto
    • Year and Date
      2007-06-09
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Photoexited charge separation properties of TiO_2 modified with dye model molecules2007

    • Author(s)
      S., Miura, K., Komaguchi, Y., Harima
    • Organizer
      The 11th Research Meeting of the ESR Forum
    • Place of Presentation
      Kyoto
    • Year and Date
      2007-06-09
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 二酸化チタン表面におけるスーパーオキシドの光化学反応2007

    • Author(s)
      駒口健治
    • Organizer
      第11回ESRフォーラム
    • Place of Presentation
      京都
    • Year and Date
      2007-06-09
    • Related Report
      2007 Annual Research Report
  • [Presentation] 色素モデル分子で修飾したTiO_2の光励起電荷分離特性2007

    • Author(s)
      駒口健治
    • Organizer
      第11回ESRフォーラム
    • Place of Presentation
      京都
    • Year and Date
      2007-06-09
    • Related Report
      2007 Annual Research Report
  • [Presentation] 還元TiO_2ナノ粒子表面に生成したO_2-のESR研究2007

    • Author(s)
      駒口健治
    • Organizer
      日本化学会第87春季年会
    • Place of Presentation
      大阪
    • Year and Date
      2007-03-25
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] An ESR study of O2- formed on partially reduced TiO_2 nanoparticles2007

    • Author(s)
      K., Komaguchi, T., Maruoka, A., Kitani
    • Organizer
      The 87th Spring Meeting of the Chemical Society of Japan
    • Place of Presentation
      Osaka
    • Year and Date
      2007-03-25
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 還元TiO_2(P25)におけるアナタースールチル粒子間の電子移動反応:ESR法による研究2006

    • Author(s)
      駒口健治
    • Organizer
      日本化学会第86春季年会
    • Place of Presentation
      船橋
    • Year and Date
      2006-03-28
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Electron transfer reactions between anatase and rutile nanoparticles in reduced TiO_2 (P25) : An ESR study2006

    • Author(s)
      K., Komaguchi, H., Nakano, A., Araki, Y., Harima
    • Organizer
      The 86th Spring Meeting of the Chemical Society of Japan
    • Place of Presentation
      Funabashi
    • Year and Date
      2006-03-28
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 還元TiO_2(P25)の光励起電子移動反応2005

    • Author(s)
      駒口健治
    • Organizer
      第44回電子スピンサイエンス学会年会(SEST2005)
    • Place of Presentation
      仙台
    • Year and Date
      2005-10-24
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] Electron transfer induced by photoexcitation in reduced TiO_2 (P25)2005

    • Author(s)
      K., Komaguchi, H., Nakano, A., Araki, Y., Omori, Y., Harima, M., Shiotani
    • Organizer
      The 44th Annual Meeting of the Society of Electron Spin Science and Technology (SEST2005)
    • Place of Presentation
      Sendai
    • Year and Date
      2005-10-24
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] 水素還元TiO_2ナノ粒子の光照射効果に関するESR研究2005

    • Author(s)
      駒口健治
    • Organizer
      2005年日本化学会西日本大会
    • Place of Presentation
      宇部
    • Year and Date
      2005-10-22
    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2007 Final Research Report Summary
  • [Presentation] An ESR study of photoeffects in TiO_2 nanoparticles reduced by hydrogen2005

    • Author(s)
      H., Nakano, K., Komaguchi, A., Araki, Y., Omori, Y., Harima, M., Shiotani
    • Organizer
      The 2005 West Japan Meeting of the Chemical Society of Japan
    • Place of Presentation
      Ube
    • Year and Date
      2005-10-22
    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2007 Final Research Report Summary

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Published: 2005-04-01   Modified: 2016-04-21  

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