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

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 (BxT1-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.