Structural and electronic properties of AuIr nanoalloys*
Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000, México, D. F., México
Received: 29 August 2012
Received in final form: 27 November 2012
Published online: 5 February 2013
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.
Key words: Topical issue: ISSPIC 16 - 16th International Symposium on Small Particles and Inorganic Clusters. Guest editors: Kristiaan Temst, Margriet J. Van Bael, Ewald Janssens, H.-G. Boyen and Françoise Remacle
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag 2013