Oxygen adsorption on anatase surfaces and edges

Oxygen adsorptions on anatase surfaces and edges are investigated with semi-empirical method MSINDO. After adsorption, an O2- forms on (1 0 1) and (1 0 0) surfaces and facets related edges, while a Ti-O-O-O-Ti bridge forms on the (0 0 1) surface or (0 0 1) surface related edges. Electrons transfer from the anatase to the adsorbed oxygen molecules which can be used to hinder the electron hole recombination during the photo-catalytic processes. Oxygen adsorption on (0 0 1) surfaces and (0 0 1) facets related edges are more energetic favorable than the adsorption on (1 0 1) and (1 0 0) facets or related edges. For the adsorptions on (1 0 1), (1 0 0) surfaces and the edges related with those two facets, edge adsorptions are more energetic favorable than the surface adsorptions. We do not see this edge effect on the (0 0 1) surface. Small size particles with more edges or particles with more (0 0 1) facets can adsorb more oxygen molecules and hinder the electron hole recombination more efficiently, and those adsorbed oxygen molecules may also oxidize other absorbed small toxic gas molecules.