Diverse melting modes and structural collapse of hollow bimetallic core-shell nanoparticles: a perspective from molecular dynamics simulations.
Introducing hollow structures into metallic nanoparticles has become a promising route to improve their catalytic performances. A fundamental understanding of thermal stability of these novel nanostructures is of significance for their syntheses and applications. In this article, molecular dynamics simulations have been employed to offer insights into the thermodynamic evolution of hollow bimetallic core-shell nanoparticles. Our investigation reveals that for hollow Pt-core/Au-shell nanoparticle, premelting originates at the exterior surface, and a typical two-stage melting behavior is exhibited, similar to the solid ones. However, since the interior surface provides facilitation for the premelting initiating at the core, the two-stage melting is also observed in hollow Au-core/Pt-shell nanoparticle, remarkably different from the solid one. Furthermore, the collapse of hollow structure is accompanied with the overall melting of the hollow Pt-core/Au-shell nanoparticle while it occurs prior to that of the hollow Au-core/Pt-shell nanoparticle and leads to the formation of a liquid-core/solid-shell structure, although both of them finally transform into a mixing alloy with Au-dominated surface. Additionally, the existence of stacking faults in the hollow Pt-core/Au-shell nanoparticle distinctly lowers its melting point. This study could be of great importance to the design and development of novel nanocatalysts with both high activity and excellent stability.
Institute of Theoretical Physics and Astrophysics, Department of Physics, Xiamen University, Xiamen, 361005, China.
Rao
R
Huang
Center for Cloud Computing and Big Data, Department of Automation, Xiamen University, Xiamen, 361005, China.
Gui-Fang
GF
Shao
Institute of Theoretical Physics and Astrophysics, Department of Physics, Xiamen University, Xiamen, 361005, China.
Xiang-Ming
XM
Zeng
Institute of Theoretical Physics and Astrophysics, Department of Physics, Xiamen University, Xiamen, 361005, China.
Yu-Hua
YH
Wen