Theoretical study of the Au/TiO2(1 1 0) interface

Different gold structures have been deposited on the defect-free rutile TiO2(1 1 0) surface. Density functional calculations show that bonding at the interface depends strongly on the Au coverage. At low coverages, the most stable site is the adsorption on the protruding O atoms while at medium coverages the fivefold coordinated Ti is preferred and at higher coverages several sites at the rutile surface are simultaneously occupied. Calculations indicate that two-dimensional (2D) or quasi-2D deposits are metastable with respect to three-dimensional ones. For large coverages, like 1 ML, we show that the strong interaction between gold and rutile TiO2(1 1 0) surface, claimed to be responsible for the enhanced reactivity of the system, does not exist for defect free supports.