Chemistry Colloquium

Size-selected model catalysts are prepared by deposition of mass-selected metal cluster cations on well characterized oxide supports. The model catalysts are characterized by x-ray photoemission spectroscopy (XPS), low energy ion scattering, and Auger electron spectroscopy. A variety of mass spectrometric methods are used to study chemical reactions catalyzed on the surface. Results for palladium clusters on alumina and titania will be present. In both cases, there are strong correlations between activity for CO oxidation and core level photoemission energies. The combination of ion scattering and XPS reveal the nature of the adsorbate bind sites, and the fate of the activated oxygen during reaction.