Thermal behavior of different types of Au–Pt–Pd nanoparticles: Dumbbell-like, three-shell, core-shell, and random-alloy

Abstract

In recent years, the synthesis of multimetallic nanoparticles with different configurations has been considered due to the special catalytic properties. Since, the catalytic performance of nanoparticles depends on their thermal stability, hence, in this study, the thermal stability of Au–Pt–Pd trimetallic nanoparticles with different configurations, including Au@PtPd core-shell, Au@Pt@Pd three-shell, AuPtPd random alloy, and Au׀Pt׀Pd dumbbell-like was compared using molecular dynamics simulation. Results showed that the Au–Pt–Pd nanoparticles with three-shell, core-shell, and random-alloy configurations are unstable at high temperature and Au atoms with less surface energy segregate to the shell and forms a spherical-like structure of Pd@AuPt with mixed shell. In addition, in the dumbbell-like nanoparticle, the penetration of Au atoms into the Pt and Pd regions leads to a spherical-like structure with a mono-layer shell of PtAu. Furthermore, results showed the following trend for thermal stability of Au–Pt–Pd nanoparticles with different configurations: three-shell ≈ random-alloy ≈ core-shell > dumbbell-like. The three-shell, random-alloy and core-shell nanoparticles with the least strain average show the highest thermal stability and the dumbbell-like nanoparticle with the most strain average shows the lowest thermal stability. Overall, the results of this study illustrate that in addition to factors such as composition, size, and morphology which have been studied in many experimental and theoretical studies, it is possible to synthesis and design of trimetallic nanoparticles with excellent catalytic activity and high thermal stability by adjusting their configuration, including three-shell, core-shell, and random alloy.