Structural optimization and melting behavior investigation of Pd-Ag bimetallic nanoparticles by molecular simulations

摘要

Pd-Ag bimetallic nanoparticles have been researched among many fields due to their excellent electronic, catalytic and optical properties. It's of great significance to learn about the corresponding structural characteristics with respect to the shape, the composition and the size from atomic scale. In present work, improved genetic algorithm accompanied by molecular statics simulations is applied to investigate the structural stability of Pd-Ag nanoparticles systematically. Specifically, the atomic arrangements of eight typical shaped Pd-Ag nanoparticles with different compositions and sizes are studied. Indicators based on energetics are used to characterize the structural stability. It has shown that the Pd-Ag nanoparticles with icosahedral shape are the most stable. Besides, the melting behavior of Pd-Ag nanoparticles is explored using molecular dynamics simulations and Lindemann index is employed to indicate the melting point It is found that the melting points increase as the size increases and the icosahedral shape of Pd-Ag nanoparticles have the highest melting points.