Thermal and structural stability evolution of Ni@Pd and Co@Pd – Understanding from molecular dynamics simulations

Abstract

Bimetallic nanoparticles are high performance materials for different fields as they can be constructed under different structures combining noble-metal nanoparticles which have been commonly used as catalysts for a variety of applications, to 3d-transition metals that have emerged as promising contenders for integration into high-performance noble-metal-based catalysts. In this study, we utilized molecular dynamics simulations to model a noble metal (Pd) and 3d-transition metals (Ni, Co), as core-shell and Janus nanoparticles to examine their thermal and structural properties. The heat of formation, melting point, surface energy, and diffusive physical characteristics are studied. The results reveal that the melting point for Co@Pd is higher than that of Ni@Pd, with the Janus nanoparticles having the larger melting points. However, Co@Pd NPs show a good stability for both structures. Based on all the observations made, it can be concluded that the thermal stability of the nanoparticles is significantly influenced by both the structure of their core and shell elements.