Regulating the Electron Distribution to Accelerate the Photocatalytic Reduction of CO2 to C2H4

How to promote the efficiency of C-C coupling is a bottleneck problem in the process of the photocatalytic reduction of CO2 to C2H4. Herein, a highly efficient photocatalyst for converting CO2 into C2H4 (with a yield of ∼12.45 μmol h-1 and a selectivity of ∼94.5%) was synthesized by implanting Ga atoms in CoS2. Ga promotes the formation of neighboring sulfur vacancies on pristine CoS2, which induces a highly asymmetric distribution of electrons around Co atoms due to the delocalization of electrons around sulfur vacancies. Theoretical calculations prove that the asymmetric electron distribution enhances the attraction between adjacent atoms, leading to a shortened distance between adjacent Coδ+ (δ = 2, 3) atoms from 3.91 to 2.49 Å. The coexistence of adjacent Coδ+ makes the d-band center closer to the Fermi level, which is conducive to the strong adsorption of *CO and subsequent *COCO dimerization. The asymmetric electronic structure between adjacent Coδ+ atoms on Ga-CoS2 provides a lower activation barrier for C-C coupling, thereby significantly promoting C2H4 formation. This study proposes a strategy to modulate the selectivity of the photocatalytic reduction of CO2 to C2H4.