title: Following the Reduction of Oxygen on TiO2 Anatase (101) Step by Step.
abstract: We have investigated the reaction between O2 and H2O, coadsorbed on the (101) surface of a reduced TiO2 anatase single crystal by scanning tunneling microscopy, density functional theory, temperature-programmed desorption, and X-ray photoelectron spectroscopy. While water adsorbs molecularly on the anatase (101) surface, the reaction with O2 results in water dissociation and formation of terminal OH groups. We show that these terminal OHs are the final and stable reaction product on reduced anatase. We identify OOH as a metastable intermediate in the reaction. The water dissociation reaction runs as long as the surface can transfer enough electrons to the adsorbed species; the energy balance and activation barriers for the individual reaction steps are discussed, depending on the number of electrons available. Our results indicate that the presence of donor dopants can significantly reduce activation barriers for oxygen reduction on anatase.
authors.affiliation: TU Wien , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Setvin
authors.affiliation: Department of Chemistry and Biochemistry, University of Bern , Freiestrasse 3, 3012 Bern, Switzerland.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Aschauer
authors.affiliation: TU Wien , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria.
authors.forename: Jan
authors.initials: J
authors.lastname: Hulva
authors.affiliation: TU Wien , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Simschitz
authors.affiliation: TU Wien , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Daniel
authors.affiliation: TU Wien , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria.
authors.forename: Michael
authors.initials: M
authors.lastname: Schmid
authors.affiliation: Department of Chemistry, Frick Laboratory, Princeton University , Princeton, New Jersey 08544, United States.
authors.forename: Annabella
authors.initials: A
authors.lastname: Selloni
authors.affiliation: TU Wien , Wiedner Hauptstrasse 8-10/134, 1040 Vienna, Austria.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Diebold