Effects of the Core Location on the Structural Stability of Ni-Au Core-Shell Nanoparticles

Martin Schnedlitz, Ricardo Fernandez-Perea, Daniel Knez, Maximilian Lasserus, Alexander Schiffmann, Ferdinand Hofer, Andreas W. Hauser*, Maria Pilar De Lara-Castells, Wolfgang E. Ernst

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

Structural changes of Ni-Au core-shell nanoparticles with increasing temperature are studied at atomic resolution. The bimetallic clusters, synthesized in superfluid helium droplets, show a centralized Ni core, which is an intrinsic feature of the growth process inside helium. After deposition on SiNx, the nanoparticles undergo a programmed temperature treatment in vacuum combined with an in situ transmission electron microscopy study of structural changes. We observe not only full alloying far below the actual melting temperature, but also a significantly higher stability of core-shell structures with decentralized Ni cores. Explanations are provided by large-scale molecular dynamics simulations on model structures consisting of up to 3000 metal atoms. Two entirely different diffusion processes can be identified for both types of core-shell structures, strikingly illustrating how localized, atomic features can still dictate the overall behavior of a nanometer-sized particle.

Original languageEnglish
Pages (from-to)20037-20043
Number of pages7
JournalThe Journal of Physical Chemistry / C
Volume123
Issue number32
DOIs
Publication statusPublished - 15 Aug 2019

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

Fields of Expertise

  • Advanced Materials Science

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