Thermodynamic Stability and Melting Mechanism of Bimetallic Au-Pt Nanoparticles

Classical molecular dynamics simulations were carried out to study the thermodynamic stability and melting behavior of Au-Pt nanoclusters of most common structural variants like decahedra, icosahedra, and cuboctahedra. It has been shown that the Pt-core/Au-shell structures are most stable, while the eutectic-like structures are more stable than solid solution ones, and the Au-core/Pt-shell are least stable, on thermal heating. On the other hand, the large difference between the melting points of the constituent elements can be a dominating factor on the melting mechanism of the bimetallic nanoparticles. The bimetallic clusters transform to the most stable Pt-core/Au-shell structure from whatever initial structures on heating above certain temperatures.