Density functional theory study of CO-induced segregation in gold-based alloys

Adnene Dhouib (1) , Myriam Sansa (2) , Hazar Guesmi (3)

1 UCAR - Université de Carthage (Tunisie)
2 UTM - Université de Tunis El Manar
3 ICGM ICMMM - Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier

This paper reports a systematic study of the effect of CO gas on the chemical composition at the surface of gold-based alloys. Using DFT periodic calculations in presence of adsorbed CO the segregation behavior of group 9-10-11 transition metals (Ag, Cu, Pt, Pd, Ni, Ir, Rh, Co) substituted in semi-infinite gold surfaces is investigated. Although, CO is found to be more strongly adsorbed on (100) than on the (111) surface, the segregation of M impurities is found to be more pronounced on the (111) surface. The results reveal two competitive effects: the effect of M on CO and the effect of CO on M. Thus, on one hand, if M exists on the (100) gold facet, CO would be strongly adsorbed on it. But if M is initially located in the bulk, it would segregate to the (111) facet instead of the (100) in order to bind to CO.

Mots clés: ACTIVATION; PALLADIUM; SPECTROSCOPY; NANOPARTICLES; CATALYSTS; AU; PD; HYDROGEN-PEROXIDE; SURFACE SEGREGATION; INITIO MOLECULAR-DYNAMICS; Surface segregation; gold-based alloys; transition metals; CO adsorption; reactive gas; DFT

Domaines: Matériaux

Adnene Dhouib, Myriam Sansa, Hazar Guesmi. Density functional theory study of CO-induced segregation in gold-based alloys. Journal of Chemical Physics, 2014, 141 (6), pp.064709. ⟨10.1063/1.4891869⟩. ⟨hal-01081152⟩