Theoretical study of the Au/TiO2(110) interface

Different gold structures have been deposited on the defect-free rutile TiO2(110) 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(110) surface, claimed to be responsible for the enhanced reactivity of the system, does not exist for defect free supports.