Density functional theory study of Ni segregation in CuNi(111) alloy with chemisorbed CO, O, or H

Abstract

Adsorption-induced surface segregation can affect the electrochemical and catalytic properties of metal alloys. We have used density functional theory to study the Ni segregation in CuNi(111) alloy in presence of adsorbed CO, O, or H. The calculated results show that adsorbates can significantly affect the Ni segregation behavior on the CuNi(111) surface. In presence of adsorbed H, the Ni atom still prefers to stay in the bulk of the alloy as under vacuum conditions, while Ni atom prefers to segregate towards the alloy surface with adsorbed CO or O. Moreover, the analysis of the adsorption behavior of these three adsorbates and the electronic structure of the alloy surface indicates that the surface-adsorbate binding strength directly affects the Ni segregation behavior on the CuNi(111) surface in a reactive environment. This study provides a theoretical basis for the practical application of Cu–Ni alloy as CO2 reduction catalysts.