Nucleation, coalescence, thermal evolution, and statistical probability of formation of Au/Ir/Pd nanoalloys in gas-phase condensation process

Abstract

Abstract There has been little investigation of the formation and the mechanism of growth of trimetallic nanoclusters in the gas condensation technique using molecular dynamics (MD) simulation. In order to address this issue, we have simulated the formation of trimetallic Au/Ir/Pd nanoalloys in gas-phase condensation. We have analysed the effect of the Au mole fraction on the structural and thermodynamic properties of the nanoclusters formed during the condensation process using MD simulation. Our stability examinations have shown that an increase of Au concentration in the Pd-Ir nanoalloy is favourable and leads to the formation of a more stable cluster. Also, we observed that the Ir atoms prefer to lie at the nanoalloy cores, but the Au and Pd atoms lie at the nanoclusters surface. The surface energy of clusters also decreases as the Au concentration increases. Also, an increase of Au atoms in the nanoalloys can increase the cluster size. The results of the structural investigations using RDF showed that a core-shell morphology has not been formed during this condensation. Some ordered structures (including fcc-like and hcp-like structures) were formed in the nanoclusters in the condensation technique. The thermal evolution study showed that the nanoalloys become more spherical by increasing the temperature. Also, the surface Ir atoms decrease with increasing temperature whereas the number of surface Au and Pd atoms vary with the temperature. We have also derived an expression for the statistical probability of formation of a three-component nanocluster.