Isolated Cu-Sn diatomic sites for enhanced electroreduction of CO2 to CO

Electrochemical CO2 reduction reaction (CO2RR) to high-value product, CO, not only provides a key feedstock for the well-established Fischer—Tropsch process but also mitigates the greenhouse effect. However, it suffers from sluggish reaction kinetics, competitive hydrogen evolution reaction, and low selectivity. Herein, we report non-precious Cu-Sn diatomic sites anchored on nitrogen-doped porous carbon (CuSn/NPC) as an efficient catalyst for CO2RR to CO. The catalyst exhibits outstanding selectivity with CO Faradaic efficiency (FE) up to 99.1%, much higher than those of individual Cu (66.2%) and Sn (51.3%) single-atom catalysts. Moreover, high stability is confirmed by consecutive 24 h electrolysis with high selectivity from CO2 to CO. Theoretical calculations reveal an obvious activation of CO2 with weakened C—O bonds and distorted CO2 configuration upon chemisorption on the CuSn/NPC catalyst. It is also suggested CuSn/NPC is more selective for the CO2RR with dominant CO production during the electrolysis, rather than the competing hydrogen evolution reaction.