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

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 s...

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Bibliographic Details
Published in:The Journal of chemical physics 2012-11, Vol.137 (19), p.194302-194302
Main Authors: Negreiros, F R, Taherkhani, F, Parsafar, G, Caro, A, Fortunelli, A
Format: Article
Language:English
Subjects:
Alloying
Barriers
Clusters
DENSITY FUNCTIONAL METHOD
Energy use
INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY
KINETIC ENERGY
KINETICS
MATERIALS SCIENCE
Nanostructure
NANOSTRUCTURES
Nuclear power generation
PHASE DIAGRAMS
Platinum
PLATINUM ALLOYS
Silver
SILVER ALLOYS
SIMULATION
VACANCIES
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Summary: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.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4759507