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-Cs 3 Bi 2 Br 9 /V 2 O 5 was successfully constructed for efficient photocatalytic CO 2 reduction to CO. • A bismuth-based perovskite Z-scheme heterojunction Cs 3 Bi 2 Br 9 /V 2 O 5 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 Cs 3 Bi 2 Br 9 /V 2 O 5 composite exhibits superior photocatalytic CO 2 reduction to CO performance. Photocatalytic reduction of CO 2 to the useful fuels has been supposed to be a hopeful approach to address currently environmental and energy problems. However, photocatalytic CO 2 reduction using H 2 O as a proton source always displays the unsatisfactory activity. Herein, a bismuth-based perovskite Z-scheme heterojunction Cs 3 Bi 2 Br 9 /V 2 O 5 with efficient charge separation and strong redox capability was fabricated for photocatalytic CO 2 reduction. The optimal Cs 3 Bi 2 Br 9 /V 2 O 5 shows a superior photocatalytic CO 2 reduction performance with a CO yield of 37.8 μmol g -1 h - 1 , which is 5.3 times higher than that of Cs 3 Bi 2 Br 9 . With the further help of the Au cocatalyst, the CO yield of the optimal Au-Cs 3 Bi 2 Br 9 /V 2 O 5 increases to 98.95 μmol g -1 h - 1 , superior to most reported perovskite photocatalytic CO 2 reduction performances. The charge transfer process and the mechanism of photocatalytic CO 2 reduction in the Au-Cs 3 Bi 2 Br 9 /V 2 O 5 composite have been thoroughly investigated. This work enriches the perovskite based Z-scheme heterojunctions and expands the application of bismuth-based perovskites in photocatalytic CO 2 reduction.