Modified Cu active sites by alloying for efficient electrocatalytic reduction CO2 to CO

Abstract

Transition metals like Au, Ag, and Cu have been reported to be quite active for CO2 reduction. In this study, we use density functional theory (DFT) calculation to investigate the electronic structure and catalytic performance of Au, Ag, Cu and their alloys for CO2 reduction reaction (CO2RR). Theoretical calculations identified the combination of Ag, Cu, and Au in a face-centered cubic (fcc) alloy as an outstanding electrocatalyst for CO2 reduction to CO, with Cu as the active site. The d-orbital projected density of state (PDOS) profile suggests that alloying alters the electronic structure of the Cu site, thereby affecting the Gibbs free energy change for the formation of *COOH intermediate (ΔG*COOH). To demonstrate the theoretical prediction experimentally, we employ a top-down dealloying approach to synthesize a nano-porous structured AgCuAu alloy (NP-Ag5Cu5Au5). Electrochemical experiments validate that the ternary alloy catalyst is clearly better than unary and binary catalysts, showing a Faradaic efficiency (FE) for CO over 90% across a broad potential range of 0.6 V, with a peak of approximately 96% at −0.573 V vs. RHE. This study underscores the potential of multi-component alloys in CO2RR and establishes a theoretical basis for designing efficient catalysts for CO2 utilization.