First-principles study of surface segregation in bimetallic Cu3M(1 1 1) (M = Au, Ag, and Zn) alloys in presence of adsorbed CO

Segregation on the surface of metal alloys has a great influence on their electrochemical and catalytic properties. We have used ab initio calculations based on density-functional theory to study the surface segregation phenomena of Cu3M(1 1 1) (M = Au, Ag, and Zn) alloy systems with chemisorbed CO. The calculated results show that the chemical adsorption of CO can substantially change the segregation tendency of Cu3M(1 1 1) surface. The stability of the M-segregated surface is higher than that of the non-segregated and Cu-segregated surfaces under vacuum condition, while the stability of the non-segregated surface is the highest at the CO coverage of 1/4 ML. Moreover, the analysis of the CO adsorption behavior and the surface electronic structure indicates that the surface-adsorbate binding strength directly affects the surface segregation tendency in a reactive environment. This study provides a theoretical basis for the practical application of copper-based alloys as CO2 reduction catalysts.