Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 5: Adsorption on semiconductors, oxides and insulators I

O 5.7: Talk

Monday, March 26, 2012, 12:00–12:15, MA 042

The adsorption of H2O on TiO2-(110) investigated by Helium Atom Scattering — •Niklas Osterloh¹ and Franziska Traeger² — ¹Physical Chemistry 1, Ruhr-University Bochum, Germany — ²Institute for Business Engineering, University of Applied Science Gelsenkirchen, Germany

Previously reported experimental and theoretical studies disagree on, whether or not water on a defect free rutile TiO2(110)-surface adsorbs dissociative. The experimental results showed almost no dissociative behavior, but theoretical studies predicted exactly the opposite. [1,2] To clarify this question, we investigated water on rutile(110) by helium atom scattering (HAS), a most surface sensitive and non-destructive method, as well as by thermal desorption spectroscopy (TDS). The angular distributions of the helium atoms clearly show a (1x1) superstructure for temperatures between 130 and 300 K. While a fully dissociated layer was ruled out by previous studies [3], this symmetry rules out any half-dissociated layer. Neither the angular distribution nor the curves of specular intensity versus temperature showed any indications for a phase transition. In this talk we will present and discuss this results.

[1] Diebold, U., The surface science of titanium dioxide. Surface Science Reports, 2003. 48: p. 53-229 [2] Pang, C.L., R. Lindsay, and G. Thornton, Chemical reactions on rutile TiO2(110). Chemical Society Reviews, 2008. 37(10): p. 2328-2353 [3] Henderson, M.A., An HREELS and TPD study of water on TiO2(110): The extent of molecular versus dissociative adsorption. Surface Science, 1996. 355(1-3): p. 151-166