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Kinetics of chemical ordering in a Ag-Pt nanoalloy particle via first-principles simulations

Negreiros, F. R ; Sharif University of Technology | 2012

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  1. Type of Document: Article
  2. DOI: 10.1063/1.4759507
  3. Publisher: 2012
  4. Abstract:
  5. The energetics and kinetic energy barriers of vacancy/atom exchange in a 37-atom truncated octahedron Ag-Pt binary cluster in the Ag-rich range of compositions are investigated via a first-principles atomistic approach. The energy of the local minima obtained considering various distributions of a single vacancy and a few Pt atoms within the cluster and the energy barriers connecting them are evaluated using accurate density-functional calculations. The effects of the simultaneous presence of a vacancy and Pt atoms are found to be simply additive when their distances are larger than first-neighbors, whereas when they can be stabilizing at low Pt content due to the release of strain by the Pt/vacancy interaction or destabilizing close to a perfect Pt(core)/Ag(shell) arrangement. It is found that alloying with Pt appreciably increases the barriers for homotops transformations, thus rationalizing the issues encountered at the experimental level in producing Ag-Pt equilibrated nanoparticles and bulk phase diagram
  6. Keywords:
  7. Atomistic approach ; Binary clusters ; Bulk phase diagrams ; Chemical ordering ; Density-functional calculations ; First-principles simulations ; Local minimums ; Nanoalloy particles ; Pt atoms ; Single vacancies ; Atoms ; Calculations ; Energy barriers ; Kinetics ; Phase diagrams ; Platinum ; Silver ; Platinum compounds
  8. Source: Journal of Chemical Physics ; Volume 137, Issue 19 , 2012 ; 00219606 (ISSN)
  9. URL: http://scitation.aip.org/content/aip/journal/jcp/137/19/10.1063/1.4759507