Categorization of atomic mixing patterns in bimetallic nanoparticles by the energy competition

The superior properties of bimetallic nanoparticles are strongly related to their morphology. A better understanding of the morphological details would be the first step to design bimetallic nanoparticles for target applications. In this study, we discussed three possible categories of atomic mixing patterns of bimetallic nanoparticles using the concept of compettition between bond energy and surface energy. The categorization was confirmed with thermodynamically stable structures of AgPt, AuPt, CuPt, PdPt, AgPd, AuPd and CuPd obtained using Monte Carlo simulations. This work also proposed phase diagrams of AuPt, CuPt and PdPt nanoparticles, which display details of atomic arrangement depending on the changes in size and atomic composition. Population in low-coordination sites, temperature effects were also intensively studied. The comprehensive understanding would facilitate rational design and wide applications of bimetallic nanoparticles.