Title: Structural characteristics and thermal stability of bimetallic Cu-Ru nanocluster

Authors: H.B. Liu, G. Carbajal-De La Torre, E. Sosa, M.A. Espinosa-Medina

Addresses: Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte No. 152, Col. San Bartolo Atepehuacan, CP 07730, Mexico DF, Mexico. ' Facultad de Ingenieria Mecanica, UMSNH, Santiago Tapia 403 Col. Centro, CP 58098, Morelia, Michoacan, Mexico. ' Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte No. 152, Col. San Bartolo Atepehuacan, CP 07730, Mexico DF, Mexico. ' Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas Norte No. 152, Col. San Bartolo Atepehuacan, CP 07730, Mexico DF, Mexico

Abstract: Classical molecular dynamics simulations were used to study the structural characteristics and thermodynamic stability of Cu-Ru nanoclusters of most common structural variants like decahedra, icosahedra and cuboctahedra. As a result, it is found that the three types of structures have consistent stability orders from the point of view of bimetallic elemental distributions. The Ru-core/Cu-shell structures and the eutectic-like structures are more stable than solid solution and Cu-core/Ru-shell. The formation energies of bimetallic clusters are consistently positive, which shows that they are not thermodynamically stable. All clusters including the unstable Cu-core/Ru-shell and solid solution clusters, and the relatively stable Ru-core/Cu-shell transform into eutectic-like cluster during heating process. Additionally, the large difference in melting point between pure Cu and pure Ru cause the Cu part in the formed eutectic-like clusters melt first and escape forming separate cluster in the further heating process.

Keywords: bimetallic nanoclusters; Cu-Ru; copper; ruthenium; molecular dynamics; simulation; thermal stability; nanotechnology.

DOI: 10.1504/IJNT.2009.028470

International Journal of Nanotechnology, 2009 Vol.6 No.12, pp.1155 - 1165

Published online: 17 Sep 2009 *

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