Eur. Phys. J. D (2013) 67: 15
https://doi.org/10.1140/epjd/e2012-30537-x

Regular Article

Structural and electronic properties of AuIr nanoalloys^*

Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000, México, D. F., México

^a e-mail: lperez@fisica.unam.mx

Received: 29 August 2012
Received in final form: 27 November 2012
Published online: 5 February 2013

Abstract

The lowest-energy structures of binary (AuIr)_n, (AuIr₃)_s, and (Au₃Ir)_s clusters, with n = 2−20, and s = 5, modeled by the many-body Gupta potential, were obtained by using a genetic-symbiotic algorithm. These structures were further relaxed within the density functional theory to obtain the most stable structures for each composition. Segregation is observed in all the AuIr clusters, where the Ir atoms occupy the cluster core and the Au atoms are situated on the cluster surface. On the other hand, there is experimental evidence that the (AuIr)_n nanoalloys could have an enhanced catalytic activity for CO oxidation. In order to study this phenomenon, we also performed first-principles density functional calculations of the CO and O₂ adsorption on these bimetallic nanoclusters, considering three different compositions and a fixed cluster size of 20 atoms.