Morphological stability of Au-metal nanosatellites

TL;DR

This study uses molecular dynamics simulations to investigate how different transition metals affect the morphological stability of gold-based core-satellite nanostructures, revealing that Rhodium enhances stability while Pt and Pd lead to structural rearrangements.

Contribution

It provides new insights into the role of transition metals in maintaining the shape and stability of gold nanostructures, which was previously underexplored.

Findings

Rh satellites are most stable over 200 ns at 600K.

Pt and Pd satellites tend to transform into spherical nanostructures.

AuRh maintains shape with minimal mixing and slow gold diffusion.

Abstract

Hybrid metallic nanoalloys combining plasmonic and catalytic metals are essential for developing advanced photocatalysts. A promising design called core-satellites comprises a spherical nanogold dotted with smaller transition-metal clusters. While these nanoalloys' catalytic activity and hot-carriers generation have been extensively studied, their morphological stability remains poorly explored. Performing molecular dynamics simulations, we highlight the critical role of the transition metal in governing the morphological stability of plasmonic core-satellites. Rh satellites exhibit the highest stability, while only 27\% Pt and 16\% Pd satellites survive after 200 ns at 600K. AuPt and AuPd quickly rearrange into single spherical nanostructures. AuPt forms icosahedra with an Au outer shell due to Au's surface diffusion. AuPd favors FCC and decahedral shapes and shows the highest Au mobility and significant Pd interdiffusion. In contrast, AuRh maintains its original shape, exhibiting a slow surface diffusion of gold onto rhodium and negligible mixing.