Document Detail


Monte Carlo simulation of surface segregation phenomena in extended and nanoparticle surfaces of Pt-Pd alloys.
MedLine Citation:
PMID:  22075765     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The surface segregation phenomena in the extended and nanoparticle surfaces of Pt-Pd alloys have been studied using the Monte Carlo (MC) simulation method and the modified embedded-atom method (MEAM) potentials developed for Pt-Pd alloys. The MEAM potentials were fitted to reproduce the experimental values of the lattice parameters, cohesive energies and surface energies of pure Pt and Pd metals, as well as the density functional theory calculation results of the lattice parameters and heat of formation of L1(2) Pt(3)Pd, L1(0) PtPd and L1(2) PtPd(3) crystal. Using the MC method and the developed MEAM potentials, we calculated the Pt concentrations in the outermost three layers of the equilibrium (111), (100) and (110) extended surfaces as well as the outermost surfaces of the equilibrium cubo-octahedral nanoparticles of Pt-Pd alloys. Our simulation results showed that the Pd atoms would segregate into the outermost layers of the extended surfaces and the Pt concentration would increase monotonically from the extended surfaces into the bulk. The equilibrium Pt-Pd nanoparticles were found to have Pd-enriched shells and Pt-enriched cores. In the shell of the Pt-Pd nanoparticles, the Pd atoms were predicted to preferably segregate to the (100) facets rather than the (111) facets.
Authors:
Zhiyao Duan; Guofeng Wang
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-11-10
Journal Detail:
Title:  Journal of physics. Condensed matter : an Institute of Physics journal     Volume:  23     ISSN:  1361-648X     ISO Abbreviation:  -     Publication Date:  2011 Nov 
Date Detail:
Created Date:  2011-11-14     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101165248     Medline TA:  J Phys Condens Matter     Country:  -    
Other Details:
Languages:  ENG     Pagination:  475301     Citation Subset:  -    
Affiliation:
Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, PA 15261, USA.
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