Structural characteristics and thermal stability of bimetallic Cu-Ru nanocluster

Classical molecular dynamics simulations were used to study the structural characteristics and thermodynamic stability of Cu-Ru nanoclusters of most common structural variants like decahedra, icosahedra and cuboctahedra. As a result, it is found that the three types of structures have consistent stability orders from the point of view of bimetallic elemental distributions. The Ru-core/Cu-shell structures and the eutectic-like structures are more stable than solid solution and Cu-core/Ru-shell. The formation energies of bimetallic clusters are consistently positive, which shows that they are not thermodynamically stable. All clusters including the unstable Cu-core/Ru-shell and solid solution clusters, and the relatively stable Ru-core/Cu-shell transform into eutectic-like cluster during heating process. Additionally, the large difference in melting point between pure Cu and pure Ru cause the Cu part in the formed eutectic-like clusters melt first and escape forming separate cluster in the further heating process.