Regularities of structural transformations in bimetallic Pd-Pt nanoparticles

Abstract

The processes of melting and crystallization of bimetallic Pt- and Pd-based nanoparticles have been studied by the method of molecular dynamics. The possibility of obtaining stable nanoparticles containing 3000 and 4000 atoms in the temperature range from 500 K to 1600 K is established. The concept about the possibility of fixing the temperatures of starting and ending of the phase transition for melting and crystallization is confirmed which was put forward earlier for monometallic platinum and palladium nanoparticles. The analysis shows that during the cooling of Pd-Pt nanoparticles with an initially uniform distribution of components, formation of a mixed structure with a surface monolayer of Pd atoms is observed. The possibility of structural segregation in bimetallic Pd-Pt nanoparticles containing 3000 and 4000 atoms is shown. At the same time, these two sizes correspond to different scenarios. For bimetallic nanoparticles with 3000 atoms, local zones are mainly polyhedral, and for bimetallic nanoparticles containing 4000 atoms, formation of extended band structures is observed.

Keywords

• molecular dynamics method
• bimetallic nanoparticles
• platinum
• palladium
• segregation
• structural transformations
• stability