Structural Evolution of the Surface and Interface in Bimetallic High-Index Faceted Heterogeneous Nanoparticles.

Bimetallic high-index faceted heterostructured nanoparticles represent a new class of high-performance nanocatalysts. In this work, we investigated the structural evolution of PtAu tetrahexahedral heterostructured nanoparticles enclosed by {210} facets using molecular dynamics simulations. The surface and interface were specifically addressed. The results show that the PtAu nanoparticle exhibits a heterogeneous melting pattern, leading to solid-liquid coexistence over a wide temperature range. In terms of particle shape evolution, the critical transformation temperature for the surface structure of the PtAu heterostructured nanoparticle is much lower than the melting point of each domain. In comparison, the interface could be basically retained even when the Au domain completely melts. These results extend our fundamental understanding of the thermally driven structural evolution of the surface and interface in bimetallic high-index faceted heterostructured nanoparticles and provide insight into the design and application of metallic nanoparticles with multifunctional performance.