上海科技大学知识管理系统

Electroreduction of CO2 to ethanol remains a formidable challenge due to the unsatisfactory efficiency of the C-C coupling process and the demand for complex oxygen-containing intermediates, thus resulting in poor selectivity and electrocatalytic activity. Cu-Ag bimetallic materials with adjustable electronic structures and active site exposure are promising catalysts to electrochemically convert CO2 to ethanol. Herein, we report Ag-decorated Cu2O materials to promote the catalytic performance of CO2 electroreduction to ethanol. The as-prepared CuAg-0.75% catalyst exhibited an improved ethanol Faradaic efficiency of 21.0% at -0.71 V (vs reversible hydrogen electrode (RHE)) and a maximum ethanol partial current density of 214.4 mA cm-2 at -0.74 V (vs RHE), which were ca. 2 times those of the counterpart without Ag decoration. Density functional theory (DFT) calculations revealed that the adsorption intensity of CO on Ag-decorated Cu surface was stronger than that on Ag surface; hence, the *CO spillover from Ag sites to Cu sites could be promoted, leading to a higher *CO coverage than that on pure Cu surface to facilitate the C-C coupling process. The evenly distributed Ag atoms provided abundant Ag sites for CO formation and a short CO transfer distance. Furthermore, the free energy of formation of key intermediates toward ethanol pathway was lower on the Ag-doped sample, which led to enhanced ethanol selectivity. Both the improved CO spillover process and the optimization of free energy on the Ag-decorated sample resulted in a better catalytic performance toward ethanol. ©