The surfaces of metal oxides

Abstract

The author reviews the present understanding of the electronic, geometric and chemisorption properties of metal oxide surfaces. It is restricted to experimental and theoretical studies of single-crystal oxide surfaces since only for those systems has it been possible to correlate surface properties with specific site geometry, ligand coordination, defect structure, etc. The geometric structures of the oxide surfaces that have been investigated to date are described in relation to bulk crystal structure and cation ligand coordination. The electronic structure of both perfect and defect surfaces is discussed for the various classes of metal oxides, and similarities and differences in their behaviour are correlated with surface geometry and cation electronic configuration. The chemisorption of several types of atoms and molecules on single-crystal oxide surfaces, both nearly perfect and containing point defects is reviewed and interpreted in terms of surface electronic and geometric structure. Some recent electron- and photon-stimulated desorption results on oxides are also reviewed, as the measurements of surface phonon and plasmon modes.