Acta Phys. -Chim. Sin. ›› 2024, Vol. 40 ›› Issue (12): 2407021.doi: 10.3866/PKU.WHXB202407021

Special Issue: Solar fuel preparation

• ARTICLE • Previous Articles     Next Articles

Revealing Photoinduced Charge Transfer Mechanism of SnO2/BiOBr S-Scheme Heterostructure for CO2 Photoreduction

Yuejiao An1, Wenxuan Liu2, Yanfeng Zhang1,*(), Jianjun Zhang3,*(), Zhansheng Lu4,2,*()   

  1. 1 National Demonstration Center for Experimental Chemistry Education, Hebei Key Laboratory of Inorganic Nano-materials, College of Chemistry and Materials Science, Hebei Normal University, Shijiazhuang 050024, China
    2 School of Physics, Henan Key Laboratory of Advanced Semiconductor & Functional Device Integration, Henan Normal University, Xinxiang 453007, Henan Province, China
    3 Laboratory of Solar Fuel, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430078, China
    4 School of Mathematics and Physics, Beijing University of Chemical Technology, Beijing 100029, China
  • Received:2024-07-23 Revised:2024-08-21 Accepted:2024-08-22 Published:2024-09-02
  • Contact: Email: zhangyanfeng@hebtu.edu.cn (Yanfeng Zhang)zslu@buct.edu.cn (Zhansheng Lu)zhangjianjun@cug.edu.cn (Jianjun Zhang)
  • Supported by:
    National Natural Science Foundation of China(12274118); National Natural Science Foundation of China(52202375); Natural Science Foundation of Hebei of China(B2020205013); Natural Science Foundation of Hebei of China(B2022205008); Science and Technology Project of Hebei Normal University of China(L2021K01); Innovation Capability Improvement Plan Project of Hebei Province(22567604H); Henan Center for Outstanding Overseas Scientists(GZS2023007); Special Project for Fundamental Research in University of Henan Province(22ZX013)

Abstract:

S-scheme heterojunctions can preserve strong redox capacity on the basis of achieving spatial separation of photogenerated carriers. Therefore, a deep comprehension of the photoinduced charge transfer dynamics in S-scheme heterostructures is vital to enhancing photocatalytic properties. Herein, SnO2/BiOBr S-scheme heterojunctions with tight contact are fabricated with in situ hydrothermal method. The optimal SnO2/BiOBr exhibits excellent photocatalytic performance for CO2 reduction, with yields of CO and CH4 of 345.7 and 6.7 μmol∙g–1∙h–1, which are 5.6 and 3.7 times higher than those of the original BiOBr. The photoinduced charge transfer mechanism and dynamics of SnO2/BiOBr S-scheme heterostructure are characterized by in situ X-ray photoelectron spectrum (XPS) and femtosecond transient absorption spectroscopy (fs-TA). A new fitted lifetime of photogenerated carriers are observed, which could be attributed to interfacial electron transfer of S-scheme heterojunction, further illustrating an ultrafast transfer channel for photoelectrons from SnO2 conduction band to BiOBr valence band. As a result, the powerful reduced electrons in BiOBr conduction band and the powerful oxidation holes in SnO2 valence band are retained. This work provides profound comprehension of photoinduced charge transfer mechanism of S-scheme heterojunction.

Key words: SnO2/BiOBr, CO2 photoreduction, S-scheme heterojunction, fs-TA, in situ XPS