Pinning mononuclear Au on the surface of titania

We have deposited Au atoms on the surface of titania without sintering or surface damage. Mass-selected Au+ atoms were deposited front the gas phase at room temperature with kinetic energies from < 3 to 190 +/- 3.5 eV. Scanning tunneling microscopy reveals island formation following deposition at < 3 eV, while mainly atomic features are observed for energies between similar to 35 and similar to 190 eV. A mixture of islands and atomic features is observed at a landing energy of 20 +/- 3.5 eV, suggesting a critical energy above which pinning occurs. Cluster size is also probed as a function of coverage in the deposition of Aul with 100 eV of energy, revealing that sintering begins at a coverage of only 0.06 ML. These observations suggest a mechanism in which high-energy collision leads to the annealing of any impact-created surface damage and the pinning of All atoms to the Surface. We provide a new method of preparing isolated ALL atoms on an oxide surface, which can serve as a platform for catalytic studies.