Ionic and radical adsorption on the Au( hkl) surfaces: A DFT study

Adsorption of several ionic and non-ionic species (OH −, O, O −, O 2−, H, H + and H −) on the low-index Miller Au( hkl) surfaces has been investigated by means of density functional theory based methods. The stability order for adsorptions on the three surfaces decreases with the increasing of the coordination number of the outermost gold atoms in each surface, i.e., Au(110) > Au(100) > Au(111), which is in agreement with the experimental evidences. The detailed COOPs analysis of the various adsorption sites for all adsorbates in the surface with the most stable adsorption(s), Au(110), evidenced that adsorption in the gold surfaces may be a function of particle size and charge and substantiates the variability in the order of preferences sites for the adsorption of the different species found in these low-index Miller Au( hkl) surfaces. This variability increases with the increasing of the stability of the adsorptions on the gold surfaces, i.e., the Au(110) presents more variability in the order of preferences sites for the adsorption of different species. ► We have studied ionic and radical adsorption on Au low-index surfaces. ► Cluster and periodic approaches, as well as different DFT functionals are analyzed. ► The Au(111) surface seems to be more sensitive to the different model approaches. ► The Au(100) and Au(110) surfaces showed to be unaffected by the choice of model. ► Adsorption on the Au(110) surface is favored independently of the methods used.