Coupling Benzylamine Oxidation with CO₂ Photoconversion to Ethanol over a Black Phosphorus and Bismuth Tungstate S‐Scheme Heterojunction

Abstract

Abstract Photoconversion of CO 2 and H 2 O into ethanol is an ideal strategy to achieve carbon neutrality. However, the production of ethanol with high activity and selectivity is challenging owing to the less efficient reduction half‐reaction involving multi‐step proton‐coupled electron transfer (PCET), a slow C−C coupling process, and sluggish water oxidation half‐reaction. Herein, a two‐dimensional/two‐dimensional (2D/2D) S‐scheme heterojunction consisting of black phosphorus and Bi 2 WO 6 (BP/BWO) was constructed for photocatalytic CO 2 reduction coupling with benzylamine (BA) oxidation. The as‐prepared BP/BWO catalyst exhibits a superior photocatalytic performance toward CO 2 reduction, with a yield of 61.3 μmol g −1 h −1 for ethanol (selectivity of 91 %).In situ spectroscopic studies and theoretical calculations reveal that S‐scheme heterojunction can effectively promote photogenerated carrier separation via the Bi−O−P bridge to accelerate the PCET process. Meanwhile, electron‐rich BP acts as the active site and plays a vital role in the process of C−C coupling. In addition, the substitution of BA oxidation for H 2 O oxidation can further enhance the photocatalytic performance of CO 2 reduction to C 2 H 5 OH. This work opens a new horizon for exploring novel heterogeneous photocatalysts in CO 2 photoconversion to C 2 H 5 OH based on cooperative photoredox systems.