Ball-Cup, Janus, core-shell and disordered-alloy rhodium-gold nanoparticles: An atomistic simulation on structural stability

In recent years, the synthesis of Au-Rh nanoparticles with different chemical arrangements have been reported. Studies indicated that the Au-Rh nanoparticles show the highly effective catalytic activity in the hydrogenation reactions at 300 K. Therefore, in this work, the stability of different chemical arrangements of Au-Rh nanoparticles, including Au-core@Rh-shell, Rh-core@Au-shell, Au-ball-Rh-cup, Rh-ball-Au-cup, Rh|Au Janus, and Au-Rh disordered-alloy, was investigated at room temperature by molecular dynamics simulation. The different parameters such as excess energy and strain were employed for comparison of stability of Au-Rh nanoparticles. Results show that the Au atoms always show the highest strain values regardless of their core or shell position. Therefore, the placement of Au atoms in the core of the nanoparticle leads to the most strain in the core position and the instability of Au-Rh nanoparticles. While, the placement of Rh atoms in the core of the nanoparticle and the placement of Au atoms in the shell of the nanoparticle lead to the reduction of the strain in the core and reduction of the surface energy in the shell, respectively, and consequently increase the stability of the Au-Rh nanoparticle. Hence, among the Au-Rh nanoparticles with different chemical arrangements, the group of Rh-ball-Au-cup, Rh|Au Janus, and Rh-core@Au-shell are known as nanoparticles with the most stability and the group of Au-core@Rh-shell, and Au-ball-Rh-cup are known as nanoparticles with the lowest stability. Meanwhile, the disordered-alloy nanoparticle shows the intermediate stability between two groups. Generally, in the Au-Rh nanoparticles with different chemical arrangements, it can be concluded that the stability of nanoparticles decreases by increasing the number of Au atoms in the positions close to the core.

Automated summary

In recent years, the stability of Au-Rh nanoparticles with different chemical arrangements at room temperature has been investigated. The results show that placing Au atoms in the core position leads to the highest strain and instability, while placing Rh atoms in the core position and Au atoms in the shell position reduces the strain and surface energy, respectively, and increases the stability of the nanoparticles. Therefore, the groups of Rh-ball-Au-cup, Rh|Au Janus, and Rh-core@Au-shell are known to have the highest stability among the different chemical arrangements of Au-Rh nanoparticles.