Hierarchical Co0.85Se‐CdSe/MoSe2/CdSe Sandwich‐Like Heterostructured Cages for Efficient Photocatalytic CO2 Reduction

Abstract Fabricating efficient photocatalysts with rapid charge carrier separation and high visible light harvesting is an advisable strategy to improve CO2 reduction performance. Herein, hierarchical Co0.85Se‐CdSe/MoSe2/CdSe cages with sandwich‐like heterostructure are prepared to act as efficient photocatalysts for CO2 reduction. In this study, the structure and composition of the final products can be regulated through the cation‐exchange reaction in the presence of ascorbic acid. In the Co0.85Se‐CdSe/MoSe2/CdSe cages, MoSe2 nanosheets function as a bridge to integrate Co0.85Se‐CdSe and CdSe on both sides of the MoSe2 nanosheet shell into a sandwich‐like heterostructured catalyst system, which possesses multiple positive merits for photocatalysis, including accelerated transport and separation of photogenerated carriers, improved visible light utilization, and increased catalytic active sites. Thus, the optimized Co0.85Se‐CdSe/MoSe2/CdSe cages exhibit remarkable visible‐light photocatalytic performance and outstanding stability for CO2 reduction with a high CO average yield of 15.04 µmol g−1 h−1 and 90.14% selectivity, which are much higher than those of other control samples including single‐component catalysts and binary hybrid catalysts. This study provides a promising way for the design and fabrication of high‐efficiency photocatalysts.