Characterization of Pt/TiO2 surfaces by means of photoelectron spectroscopy of adsorbed xenon

Photoelectron spectroscopy of adsorbed Xe (PAX) was used to characterize various Pt/TiO2 (100) surfaces on an atomic scale. The PAX data provide useful information on both geometrical and electronic states of various surface sites. For example, both Ar ion sputtering and high temperature annealing (850 °C) in vacuum produce a distribution of (high charge density) surface defect sites, most likely Ti3+ and Ti2+, whose local surface potentials are higher than on a stoichiometric TiO2 surface by 0.5 and 1 eV, respectively. Submonolayer deposits of Pt on a stoichiometric TiO2 exhibits much lower local surface potentials (0.5–1 eV) than sputter‐roughened bulk Pt, suggesting modified charge densities at these sites.