In situ preparation of a novel Z-scheme BiOBr/BiVO4 composite film with enhanced photocatalytic CO2 reduction performance

A kind of novel Z-scheme BiOBr/BiVO4 composite film has been successfully synthesized on a Bi plate by the electrochemical ion-exchange method using BiOBr nanosheets as the template and NH4VO3 as the ion-exchange source. Under simulated sunlight irradiation, the BiOBr/BiVO4 composite film exhibits excellent photocatalytic CO2 reduction activity to CO with a production rate of 95.27 μmol g−1 h−1, 1.62 and 1.39 times higher than that of pure BiVO4 and BiOBr, respectively, which should be attributed to the significantly enhanced separation of photogenerated carriers owing to the formation of a Z-scheme heterojunction structure between BiOBr and BiVO4 interfaces. The Z-type transfer path of photoinduced electrons in BiOBr/BiVO4 composite films is confirmed through the calculated work functions of BiOBr and BiVO4 using density functional theory (DFT). This work should provide new important insights into the immobilization of highly efficient Bi-based photocatalysts and their application in the photocatalytic CO2 green conversion into high value-added chemicals or fuels.