The first-principle study of the iodine-modified silver surfaces

The properties of the I-modified Ag(1 1 1), (1 0 0) and (1 1 0) surfaces are studied via the first-principle local density functional calculation with the ultrasoft pseudopotential and the generalized gradient approximation. The preferred adsorption site, relaxation of the surface structure, adsorption energy, work function change and changes of the properties with the coverage as well as total density of state are investigated. The most energetically favorite adsorption site is hollow site on the (1 0 0) surface in our study. Strong interaction between the iodine atom and the surface and transfer of electronic charges from the silver surface to the iodine atom are observed. The function of the iodine atom in the partial oxidation of the methanol is discussed based on our results.