An Efficient Strategy for Tailoring Interfacial Charge Transfer Pathway on Semiconductor Photocatalysts: A Case of (BiFeO3)x(SrTiO3)1−x/Mn3O4

Abstract

The ability to generate heterostructures with a desirable charge transfer pathway is essential for achieving semiconductor photocatalysts with super photocatalytic activity. Herein, it is proposed to realize robust tailoring of effective charge transfer pathway in semiconductor-based heterostructures via work function regulation, and elucidate the influence of the work function of the semiconductor on the charge transfer mechanism at the heterostructure interface. Specifically, taking type-II heterostructure SrTiO₃/Mn₃O₄ as an example, introducing BiFeO₃ into SrTiO₃ effectively regulate the work function of the (BiFeO₃)_x(SrTiO₃)_1−x/Mn₃O₄ (B_xT_1−x/Mn₃O₄) solid solution through optimizing the x value. Combined with in situ testing, the results show that the original type-II heterojunction SrTiO₃/Mn₃O₄ is converted into S-scheme heterojunction (BiFeO₃)_0.3(SrTiO₃)_0.7/Mn₃O₄ when BiFeO₃ is introduced. This increases the work function of the semiconductor, inducing the light-generated carriers to be guided and separated by the generated built-in electric field. Therefore, the implementation of this strategy can achieve efficient photocatalytic CO₂ reduction. In contrast to pristine SrTiO₃/Mn₃O₄, the (BiFeO₃)_0.3(SrTiO₃)_0.7/Mn₃O₄ heterostructure exhibits a 28-fold enhancement of in electron consumption rate during photocatalytic CO₂ reduction, and the reaction mechanism is suggested. In this study, a strategy for effectively converting interfacial charge transfer pathways in semiconductor photocatalysts is developed to enhance the photoconversion kinetics of CO₂ and H₂O.