Efficient charge transfer in cadmium sulfide quantum dot-decorated hierarchical zinc sulfide-coated tin disulfide cages for carbon dioxide photoreduction

Constructing hybrid photocatalysts with advanced structures and controllable compositions is a promising way to improve CO2 photoreduction performance. In this work, SnS2 nanosheets are grown on ZnS polyhedron cages to fabricate hierarchical ZnS@SnS2 double-shelled heterostructured cages. This design integrates ZnS cages and SnS2 nanosheets into a stable heterostructured hybrid catalyst with a hierarchical double-shelled cage-like architecture, possessing abundant active sites, quick charge separation/migration, and high CO2 adsorption capacity. Benefiting from these advantages, the optimized hierarchical ZnS@SnS2 heterostructured cages exhibit significant gas-phase CO2 photoreduction activity with a CO generation rate of 95.38 μmol g-1h-1 and 72.4% CO selectivity, which are greatly improved in comparison with those of pure ZnS cages and nanosheet-assembled SnS2 particles. Furthermore, charge carrier separation efficiency and visible light harvesting ability are further improved by constructing a ZnS@SnS2/CdS type-I/type-II complex heterostructured system through surface decoration of CdS quantum dots. The optimized ZnS@SnS2/CdS hybrid exhibits a CO generation rate of 155.57 μmol g-1h-1 and an excellent selectivity of 80.4%. This work is conducive to the design and manufacture of advanced hybrids for solar energy utilization and photocatalytic reactions.