The structure-function relationships in selective oxidation reactions over metal oxides

Oxidation catalysis over metal oxide surfaces continues to pose major challenges for catalysis researchers. The surface of a metal oxide catalyst under reaction conditions is a dynamic one, with multiple adsorption-desorption, reduction-oxidation steps taking place. Lattice oxygen diffusion, formation of defects and surface restructuring may all be important molecular processes that play a role in determining the catalytic performance. Although, catalytic activity is often thought of in terms of a single active site, the determining factor for activity and selectivity may be a combination of several competing phenomena, involving multiple active sites and/or their interaction and proximity to each other. Some of the earlier work that addressed the questions regarding structural specificity, synergy, role of promoters, and support effects are reviewed in an effort to provide examples of structure-function relationships of metal oxide catalysts in oxidation reactions.