Through an interplay between scanning tunnelling microscopy and density functional theory calculations, it was shown that bridging oxygen vacancies were the active nucleation sites for Au clusters on the rutile TiO2(110) surface. It was found that a direct correlation existed between a decrease in the density of vacancies and the amount of Au deposited. From density functional theory calculations, it was found that the oxygen vacancy was indeed the strongest Au binding site. It was shown, both experimentally and theoretically, that a single oxygen vacancy could bind three Au atoms on average. In view of these results, a new growth model for the TiO2(110) system involving vacancy-cluster complex diffusion was proposed.

Bonding of Gold Nanoclusters to Oxygen Vacancies on Rutile TiO2(110). Wahlström, E., Lopez, N., Schaub, R., Thostrup, P., Rønnau, A., Africh, C., Lægsgaard, E., Nørskov, J.K., Besenbacher, F.: Physical Review Letters, 2003, 90[2], 026101