Reverse Electron Transfer-Induced SnS2 Phase Transition for Efficient Photocatalytic CO2–C2H6 Conversion

Abstract

Two-dimensional metal sulfides such as SnS₂ play a pivotal role in the field of environmental energy due to their suitable optical bandgap and high specific surface area. However, the steady-state 2H-phase SnS₂ suffers from rapid charge recombination and low CO₂ catalytic activity, limiting its practical application in photocatalytic CO₂ reduction. In this work, we designed a CuPd/SnS₂ heterojunction system by loading CuPd nanoparticles onto SnS₂ nanosheets (NSs). Under illumination, the hot electrons excited in CuPd nanoparticles induce a 2H-1T-phase transition of SnS₂, effectively improving the photogenerated carrier dynamics of the material. Additionally, the post-transition energy level structure facilitates more efficient injection of photogenerated electrons into highly catalytic CuPd particles, achieving the goal of photocatalytic reduction of CO₂ to C₂H₆. Resultingly, the CuPd/SnS₂ photocatalytic system achieves a C₂H₆ production rate of 255.6 μmol g^–1 h^–1, which is approximately 24.4 times and 3.9 times higher than that of Cu/SnS₂ and Pd/SnS₂, respectively. Moreover, it boasts a remarkable product selectivity of up to 90.4% for C₂H₆. This study provides a valuable approach for modulating photogenerated carrier dynamics and enhancing catalytic activity in two-dimensional metal sulfides.