Reverse Electron\nTransfer-Induced SnS<sub>2</sub> Phase\nTransition for Efficient Photocatalytic CO<sub>2</sub>–C<sub>2</sub>H<sub>6</sub> Conversion

Two-dimensional metal sulfides such as SnS<sub>2</sub> play a pivotal\nrole in the field of environmental energy due to their suitable optical\nbandgap and high specific surface area. However, the steady-state\n2H-phase SnS<sub>2</sub> suffers from rapid charge recombination and\nlow CO<sub>2</sub> catalytic activity, limiting its practical application\nin photocatalytic CO<sub>2</sub> reduction. In this work, we designed\na CuPd/SnS<sub>2</sub> heterojunction system by loading CuPd nanoparticles\nonto SnS<sub>2</sub> nanosheets (NSs). Under illumination, the hot\nelectrons excited in CuPd nanoparticles induce a 2H-1T-phase transition\nof SnS<sub>2</sub>, effectively improving the photogenerated carrier\ndynamics of the material. Additionally, the post-transition energy\nlevel structure facilitates more efficient injection of photogenerated\nelectrons into highly catalytic CuPd particles, achieving the goal\nof photocatalytic reduction of CO<sub>2</sub> to C<sub>2</sub>H<sub>6</sub>. Resultingly, the CuPd/SnS<sub>2</sub> photocatalytic system\nachieves a C<sub>2</sub>H<sub>6</sub> production rate of 255.6 μmol\ng<sup>–1</sup> h<sup>–1</sup>, which is approximately\n24.4 times and 3.9 times higher than that of Cu/SnS<sub>2</sub> and\nPd/SnS<sub>2</sub>, respectively. Moreover, it boasts a remarkable\nproduct selectivity of up to 90.4% for C<sub>2</sub>H<sub>6</sub>.\nThis study provides a valuable approach for modulating photogenerated\ncarrier dynamics and enhancing catalytic activity in two-dimensional\nmetal sulfides.