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

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.