Chinese Journal of Catalysis ›› 2021, Vol. 42 ›› Issue (5): 808-816.DOI: 10.1016/S1872-2067(20)63688-9

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Time-resolved infrared spectroscopic investigation of Ga2O3 photocatalysts loaded with Cr2O3-Rh cocatalysts for photocatalytic water splitting

Qian Dinga,b, Tao Chena,c, Zheng Lia, Zhaochi Fenga, Xiuli Wanga,*()   

  1. aState Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian National Laboratory for Clean Energy, Dalian 116023, Liaoning, China
    bUniversity of Chinese Academy of Sciences, Beijing 100049, China
    cSchool of Marine Science and Environment Engineering, Dalian Ocean University, Dalian 116023, Liaoning, China
  • Received:2020-05-01 Accepted:2020-05-01 Online:2021-05-18 Published:2021-01-29
  • Contact: Xiuli Wang
  • About author:* Tel: +86-411-84379027; Fax: +86-411-84694447; E-mail: xiuliwang@dicp.ac.cn
    First author contact:

    These authors equally contributed to the work.

  • Supported by:
    National Natural Science Foundation of China(21633015);National Natural Science Foundation of China(21872143);National Natural Science Foundation of China(21761142018);973 National Basic Research Program of the Ministry of Science and Technology of China(2014CB239400);Guidance Program of Natural Science Foundation of Liaoning Province(201602097)

Abstract:

Investigation of the charge dynamics and roles of cocatalysts is crucial for understanding the reaction of photocatalytic water splitting on semiconductor photocatalysts. In this work, the dynamics of photogenerated electrons in Ga2O3 loaded with Cr2O3-Rh cocatalysts was studied using time-resolved mid-infrared spectroscopy. The structure of these Cr2O3-Rh cocatalysts was identified with high-resolution transmission electron microscopy and CO adsorption Fourier-transform infrared spectroscopy, as Rh particles partly covered with Cr2O3. The decay dynamics of photogenerated electrons reveals that only the electrons trapped by the Rh particles efficiently participate in the H2 evolution reaction. The loaded Cr2O3 promotes electron transfer from Ga2O3 to Rh, which accelerates the electron-consuming reaction for H2 evolution. Based on these observations, a photocatalytic water-splitting mechanism for Cr2O3-Rh/Ga2O3 photocatalysts has been proposed. The elucidation of the roles of the Cr2O3-Rh cocatalysts aids in further understanding the reaction mechanisms of photocatalytic water splitting and guiding the development of improved photocatalysts.

Key words: Time-resolved mid-infrared spectroscopy, Carrier dynamics, Overall water splitting, Cocatalyst, Gallium oxide, Photocatalysis, Time-resolved mid-infrared spectroscopy, Carrier dynamics, Overall water splitting, Cocatalyst, Gallium oxide