Potential-Dependent Atomic Dissolution and Segregation of Cu and Pt Surfaces

Abstract

Cu and Pt are two of the most commonly studied transition metal catalysts for electrochemical reactions. However, the potential-dependent dissolution and segregation behavior of these catalysts are poorly understood. In this contribution, we employed an advanced-homogeneous background charge method (A-HBM) to understand the dissolution of Cu/Pt from the (111) facet as solvated Cu²⁺/Pt²⁺ ions. The results from A-HBM calculations predicted the equilibrium potentials of the Cu(111)–Cu²⁺ and Pt(111)–Pt²⁺ transitions to be 0.46 and 1.37 V, respectively, with respect to a standard hydrogen electrode (SHE), in close agreement with the experimental values. Furthermore, we expanded our investigation to study the potential-dependent segregation of Cu and Pt on the (111) surfaces. Our calculations showed that after the initial oxidation and dissolution of metal atoms from the surfaces, the segregation process is kinetically challenging because of the high energy barriers associated with segregation at any potential other than equilibrium potentials. The results from this study demonstrate that the applied external potential-dependent stability, particularly dissolution, and segregation, of catalyst surfaces can be accurately predicted from charged density functional theory calculations when combined with the A-HBM.