Phase stability of Pt nanoclusters and the effect of a (0001) graphite surface through molecular dynamics simulation

Abstract

38, 147, 309 and 561 atoms) nanoclusters under various temperature conditions. The heating and freezing behaviors show that the Pt (147), Pt-309 and Pt-561 clusters have icosahedral morphologies in the temperature range of 460-660 K during freezing, where their formation energies are 0.051 eV/atom for Pt-147, 0.056 eV/atom for Pt-309, and 0.067 eV/atorn for Pt-561. The calculation of the free energy change, which is based on the Gibbs-Thomson effect, implies that the coalescence phenomenon of the nanoclusters is a thermodynamically stable process. On a (0 0 0 1) graphite surface, the bottom layer of a Pt nanocluster is rearranged to a close-packed plane due to the arrangements of carbon atoms on the graphite surface, and this rearrangement disturbs the formation of a spherical Pt cluster. (c) 2008 Elsevier B.V. All rights reserved.