A direct Z-scheme heterojunction of CsPbBr3/SnS2 nanosheets for visible light-driven photocatalytic CO2 reduction

Abstract

Z-Scheme heterojunctions with strong redox capability and efficient photoinduced carrier separation are critical for sunlight-driven CO₂ conversion, yet their optimal structural arrangement remains to be improved. Herein, we report a 2D/2D CsPbBr₃/SnS₂ nanosheet hybrid system featuring an extensive interfacial contact area that facilitates photoinduced carrier transfer. The inbuilt electric field directs photoinduced electrons to accumulate on CsPbBr₃, while holes migrate to SnS₂, thereby enhancing their respective redox capabilities. This system achieves a maximum CO rate of 75.6 µmol g⁻¹ h⁻¹, representing a 32.8-fold and 3.5-fold improvement compared to pristine 2D SnS₂ and CsPbBr₃–OA, respectively. Electrochemical characterization reveals that interlayer hybridization synergistically enhances both interfacial carrier transfer and surface redox ability. The electrostatic assembly approach enables the controlled synthesis of various CsPbBr₃/SnS₂ composites with tunable SnS₂ ratios, providing a generalizable strategy for the precise fabrication of dual crystal facet-exposed catalysts.