title: First-principles study of Au-Cu alloy surface changes induced by gas adsorption of CO, NO, or O2.
abstract: The surface composition of bimetallics can be strongly altered by adsorbing molecules where the metal with the strongest interaction with the adsorbate segregates into the surface. To investigate the effect of reactive gas on the surface composition of Au-Cu alloy, we examined by means of density functional theory to study the segregation behavior of copper in gold matrices. The adsorption mechanisms of CO, NO, and O2 gas molecules on gold, copper, and gold-copper low index (111), (100), and (110) surfaces were analyzed from energetic and electronic points of view. Our results show a strong segregation of Cu toward the (110) surface in the presence of all adsorbed molecules. Interestingly, the Cu segregation toward the (111) and (100) surface could occur only in the presence of CO and at a lower extent in the presence of NO. The analysis of the electronic structure highlights the different binding characters of adsorbates inducing the Cu segregation.
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR5253 UM/CNRS/ENSCM, 8 Rue de l'Ecole Normale, 34296 Montpellier, France.
authors.forename: Marwa
authors.initials: M
authors.lastname: Dhifallah
authors.affiliation: College of Science, Department of Chemistry, University of Dammam, Dammam, Saudi Arabia.
authors.forename: Adnene
authors.initials: A
authors.lastname: Dhouib
authors.affiliation: College of Science, Department of Chemistry, University of Dammam, Dammam, Saudi Arabia.
authors.forename: Sarah
authors.initials: S
authors.lastname: Aldulaijan
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR5253 UM/CNRS/ENSCM, 8 Rue de l'Ecole Normale, 34296 Montpellier, France.
authors.forename: Francesco
authors.initials: F
authors.lastname: D I Renzo
authors.affiliation: Institut Charles Gerhardt Montpellier, UMR5253 UM/CNRS/ENSCM, 8 Rue de l'Ecole Normale, 34296 Montpellier, France.
authors.forename: Hazar
authors.initials: H
authors.lastname: Guesmi