Surface Segregation and Structural Features of Bimetallic Au−Pt Nanoparticles

Abstract

Monte Carlo simulations were carried out to systematically investigate the effects of composition, size, and temperature on the surface segregation and structural features of Au−Pt nanoparticles in the present paper. A strong surface Au enrichment was observed in all of the nanoparticles, and the surface segregation of Au was promoted by increasing the particle sizes. It is found that the core−shell structure was preferred in the equilibrium Au−Pt nanoparticles with low Au composition, and three-shell onion-like structure was formed at high Au composition. The competitive multisite segregation was predicted in the core−shell nanoparticles in which Au atoms favor sites at the vertices, edges, and facets. The reverse temperature dependency of segregation for different surface sites has also been discussed.