Achieving Tunable Selectivity and Activity of CO Electroreduction to CO via Bimetallic Silver-Copper Electronic Engineering.

Limited comprehension of the reaction mechanism has hindered the development of catalysts for CO reduction reactions (CO RR). Here, the bimetallic AgCu nanocatalyst platform is employed to understand the effect of the electronic structure of catalysts on the selectivity and activity for CO electroreduction to CO. The atomic arrangement and electronic state structure vary with the atomic ratio of Ag and Cu, enabling tunable d-band centers to optimize the binding strength of key intermediates. Density functional theory calculations confirm that the variation of Cu content greatly affects the free energy of *COOH, *CO (intermediate of CO), and *H (intermediates of H ), which leads to the change of the rate-determining step. Specifically, Ag Cu reduces the free energy of the formation of *COOH while maintaining a relatively high theoretical overpotential for hydrogen evolution reaction(HER), thus achieving the best CO selectivity. While Ag Cu shows relatively low formation energy of both *COOH and *H, the compromised thermodynamic barrier and product selectivity allows Ag Cu the best CO partial current density. This study realizes the regulation of the selectivity and activity of electrocatalytic CO to CO, which provides a promising way to improve the intrinsic performance of CO RR on bimetallic AgCu.