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

Abstract

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 Co^δ+ (δ = 2, 3) atoms from 3.91 to 2.49 Å. The coexistence of adjacent Co^δ+ makes the <i>d</i>-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 Co^δ+ 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.