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

Abstract

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.