Cooperative phase-separated Cu–Zn catalyst for selective CO2 electrochemical reduction toward ethanol: theoretical insights into the role of the interface sites

Abstract

Bimetallic Cu–Zn electrocatalysts have emerged as promising candidates for selectively reducing carbon dioxide (CO₂) to ethanol. While CO₂ reduction reaction (CO₂RR) has been studied extensively on monometallic Cu and Zn catalysts and their homogenous alloys, the influence of heterogeneous Cu–Zn interfaces remain underexplored. Herein, we used density functional theory (DFT) calculations to investigate the interface effects of phase-separated Cu–Zn catalysts on CO₂RR toward ethanol. Interface sites significantly modulate intermediate stability and enhance the C–C coupling step, particularly CO–CH coupling, which is both thermodynamically and kinetically favorable (ΔG_rxn =  −1.28 eV; ΔG^‡ = 0.27 eV). Interface site favors the ethanol pathway over ethylene after subsequent *CHCO formation. Microkinetic analysis further suggests that CO–CH coupling dominantly contributes to the ethanol production. These findings reveal the cooperative role of interface sites in enabling selective ethanol production, providing insights into the rational design of Cu–Zn electrocatalysts.