Manipulating C-C coupling pathway in electrochemical CO reduction for selective ethylene and ethanol production over single-atom alloy catalyst.

Manipulation C-C coupling pathway is of great importance for selective CO electroreduction but remain challenging. Herein, two model Cu-based catalysts, by modifying Cu nanowires with Ag nanoparticles (AgCu NW) and Ag single atoms (AgCu NW), respectively, are rationally designed for exploring the C-C coupling mechanisms in electrochemical CO reduction reaction (CORR). Compared to AgCu NW, the AgCu NW exhibits a more than 10-fold increase of C selectivity in CO reduction to ethanol, with ethanol-to-ethylene ratio increased from 0.41 over AgCu NW to 4.26 over AgCu NW. Via a variety of operando/in-situ techniques and theoretical calculation, the enhanced ethanol selectivity over AgCu NW is attributed to the promoted HO dissociation over the atomically dispersed Ag sites, which effectively accelerated *CO hydrogenation to form *CHO intermediate and facilitated asymmetric *CO-*CHO coupling over paired Cu atoms adjacent to single Ag atoms. Results of this work provide deep insight into the C-C coupling pathways towards target C product and shed light on the rational design of efficient CORR catalysts with paired active sites.