Effect of Size and Composition on the Structural Stability of Pt–Ni Nanoalloys

Abstract

Pt–Ni nanoalloys have attracted many attentions for their catalytic applications, but their structural stability at different sizes and compositions still remains unclear. In this work, we systematically study the equilibrium structure of the Pt–Ni nanoalloys with different sizes of 38, 55, 147 and 309 atoms and compositions using genetic algorithm (GA) method, based on the Gupta potentials. It was found that the Pt–Ni nanoalloys with the composition of Pt0.55Ni0.45 have the most stable structures among these structures. Moreover, all the most stable structures of Pt–Ni nanoalloys exhibited the icosahedron (ICO) structures at different sizes. In addition, the effect of composition on the structural stability of Pt–Ni nanoalloys can be explained by the relative atomic mixing degree of the nanoalloys measured by bond order parameter and the number of Pt–Ni bond. This work highlights a simply and useful roadmap to study the structural stability of metal nanoalloys by atomistic simulations, which is of fundamental interest for both theorists and experimentalists.