Theoretical Study on the Structural, Thermal and Phase Stability of Pt–Cu Alloy Clusters

Abstract

Pt-based cluster have received much attention for their catalytic applications, while its stability property and phase diagram remain unclear. In this work, the structural, thermal and phase stability of Pt–Cu nanoclusters, with various atomic arrangement, morphologies and sizes, are studied by both atomistic simulations and theoretical model. Pt atoms tend to distribute around the surface and Cu atoms prefer occupying inner core, derived from the surface energies, lattice parameters and the binding energy of the metal bond. Furthermore, we focus on the melting points and phase diagrams of Pt–Cu nanoalloys with different morphologies and sizes. The melting point of Pt–Cu nanoparticles rises with the increasing size. The distribution of Pt atoms along surface enhances the structural and thermal stability of the Pt–Cu nanoalloys. This theoretical work serve as a case to explore the stability and segregation properties of nanoalloys by combining atomistic simulations and theoretical model, which provides a deep insight into the effect on the stability and segregation properties of bimetallic nanoparticles.