Manipulating C-C coupling pathway in electrochemical CO2 reduction for selective ethylene and ethanol production over single-atom alloy catalyst

Abstract

Manipulation C-C coupling pathway is of great importance for selective CO₂ electroreduction but remain challenging. Herein, two model Cu-based catalysts, by modifying Cu nanowires with Ag nanoparticles (AgCu NW) and Ag single atoms (Ag₁Cu NW), respectively, are rationally designed for exploring the C-C coupling mechanisms in electrochemical CO₂ reduction reaction (CO₂RR). Compared to AgCu NW, the Ag₁Cu NW exhibits a more than 10-fold increase of C₂ selectivity in CO₂ reduction to ethanol, with ethanol-to-ethylene ratio increased from 0.41 over AgCu NW to 4.26 over Ag₁Cu NW. Via a variety of operando/in-situ techniques and theoretical calculation, the enhanced ethanol selectivity over Ag₁Cu NW is attributed to the promoted H₂O 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 C₂₊ product and shed light on the rational design of efficient CO₂RR catalysts with paired active sites.