Construction of a bismuth-based perovskite direct Z-scheme heterojunction Au-Cs3Bi2Br9/V2O5 for efficient photocatalytic CO2 reduction

A bismuth-based perovskite direct Z-scheme heterojunction Au-Cs3Bi2Br9/V2O5 was successfully constructed for efficient photocatalytic CO2 reduction to CO. [Display omitted] •A bismuth-based perovskite Z-scheme heterojunction Cs3Bi2Br9/V2O5 has been successfully fabricated.•The Z-scheme charge transfer process was clearly verified.•Z-scheme charge transfer effectively promotes the spatial separation of charge carriers with strong redox ability.•The Au loaded Cs3Bi2Br9/V2O5 composite exhibits superior photocatalytic CO2 reduction to CO performance. Photocatalytic reduction of CO2 to the useful fuels has been supposed to be a hopeful approach to address currently environmental and energy problems. However, photocatalytic CO2 reduction using H2O as a proton source always displays the unsatisfactory activity. Herein, a bismuth-based perovskite Z-scheme heterojunction Cs3Bi2Br9/V2O5 with efficient charge separation and strong redox capability was fabricated for photocatalytic CO2 reduction. The optimal Cs3Bi2Br9/V2O5 shows a superior photocatalytic CO2 reduction performance with a CO yield of 37.8 μmol g-1 h-1, which is 5.3 times higher than that of Cs3Bi2Br9. With the further help of the Au cocatalyst, the CO yield of the optimal Au-Cs3Bi2Br9/V2O5 increases to 98.95 μmol g-1 h-1, superior to most reported perovskite photocatalytic CO2 reduction performances. The charge transfer process and the mechanism of photocatalytic CO2 reduction in the Au-Cs3Bi2Br9/V2O5 composite have been thoroughly investigated. This work enriches the perovskite based Z-scheme heterojunctions and expands the application of bismuth-based perovskites in photocatalytic CO2 reduction.