Thermal profile analysis in simulation of the initial stage of synthesis of Cu–Au nanoparticles from the gas phase

The production of particles from the gas phase is one of the main physical methods for the synthesis of nanostructured materials, the obvious advantages of which include good control of the target composition of the resulting nanomaterial. However, the determination of clear dependences between the initial parameters of experimental setups and the size of nanoparticles is not an easy task, requiring a detailed study of the processes of formation, growth, and agglomeration of nanoclusters. Another problem is that metal nanoparticles of identical chemical composition and size can be in different structural states or have different levels of defects. The processes underlying the formation of the structure of such nanoparticles are also not completely clear, especially at the very initial stage of synthesis from the moment of decomposition of precursors to the formation of primary stable nuclei. Therefore, in the presented work, the molecular dynamics method was used to simulate the process of synthesis of Cu–Au nanoclusters of various target compositions from the high-temperature gas phase. Based on the data obtained, conclusions were drawn about the main stages of the evolution of the model system. It is shown that the initial stage of synthesis consists of five different stages, gradually leading to the formation of primary spherical Cu–Au binary alloy nanoparticles with a clear extrusion of gold atoms to the surface.