Water adsorption at the tetrahedral titania surface layer of SrTiO3(110)-(4 × 1)

Z. Wang, X. Hao, S. Gerhold, Z. Novotny, C. Franchini, E. McDermott, K. Schulte, M. Schmid, U. Diebold

Institut für Angewandte Physik, Technische Universität Wien, 1040 Wien, Austria
Faculty of Physics & Center for Computational Material Science, University of Vienna, 1090 Wien, Austria
Institute of Materials Chemistry, Vienna University of Technology, 1060 Wien, Austria
MAX IV Laboratory, Lund University, 22100 Lund, Sweden

J. Phys. Chem. C 117 (2013) 26060-26069

The interaction of water with oxide surfaces is of great interest for both fundamental science and applications. We present a combined theoretical [density functional theory (DFT)] and experimental [Scanning Tunneling Microscopy (STM), photoemission spectroscopy (PES)] study of water interaction with the two-dimensional titania overlayer that terminates the SrTiO3(110)-(4 × 1) surface and consists of TiO4 tetrahedra. STM, core-level and valence band PES show that H2O neither adsorbs nor dissociates on the stoichiometric surface at room temperature, while it dissociates at oxygen vacancies. This is in agreement with DFT calculations, which show that the energy barriers for water dissociation on the stoichiometric and reduced surfaces are 1.7 and 0.9 eV, respectively. We propose that water weakly adsorbs on two-dimensional, tetrahedrally coordinated overlayers.

Corresponding author: Ulrike Diebold (diebold at iap_tuwien_ac_at).

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