Adjusted Preferential Adsorption of Intermediates via Regulation of the Electronic Structure during the Electrocatalytic CO 2 Reduction Process.

The surface electronic structures of catalysts play a crucial role in CO 2 adsorption and activation. Here, sulfur vacancies are introduced into CuInS 2 nanosheets (V s -CuInS 2 ) to evaluate the effect of electronic structures at the surface-active sites on the electrochemical CO 2 reduction reaction (CO 2 RR). V s -CuInS 2 exhibits a significant disparity in the highest FE formate /FE CO (6.50) compared to that of CuInS 2 (1.86). Specifically, the maximum current density ( J max ) of carbon products on V s -CuInS 2 is 78.78 mA cm -2 , and a Faraday efficiency of carbon products (FE carbon products ) of ≥80% is achieved in 600 mV wide potential windows. In situ Raman measurements and density functional theory calculations elucidate the origin of the apparent alterations in the carbon product selectivity. The introduction of sulfur vacancies realizes the controllable regulation of the local electronic density around the metal active sites, inducing the transformation of *COOH and *OCHO from competitive adsorption on CuInS 2 to specific adsorption on V s -CuInS 2 . In addition, the regulation of electronic structures on V s -CuInS 2 inhibits *H adsorption. This work reveals the transfer of adsorption of CO 2 RR intermediates via regulation of the electronic structure, complementing the understanding of the mechanism for the enhanced CO 2 RR.