Surface Structure of TiO2 Rutile (011) Exposed to Liquid Water

Jan Balajka, Ulrich Aschauer, Stijn F.L. Mertens, Annabella Selloni, Michael Schmid, Ulrike Diebold

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17 Scopus citations

Abstract

The rutile TiO2(011) surface exhibits a (2 × 1) reconstruction when prepared by standard techniques in ultrahigh vacuum (UHV). Here we report that a restructuring occurs upon exposing the surface to liquid water at room temperature. The experiment was performed in a dedicated UHV system, equipped for direct and clean transfer of samples between UHV and liquid environment. After exposure to liquid water, an overlayer with a (2 × 1) symmetry was observed containing two dissociated water molecules per unit cell. The two OH groups yield an apparent "c(2 × 1)" symmetry in scanning tunneling microscopy (STM) images. On the basis of STM analysis and density functional theory (DFT) calculations, this overlayer is attributed to dissociated water on top of the unreconstructed (1 × 1) surface. Investigation of possible adsorption structures and analysis of the domain boundaries in this structure provide strong evidence that the original (2 × 1) reconstruction is lifted. Unlike the (2 × 1) reconstruction, the (1 × 1) surface has an appropriate density and symmetry of adsorption sites. The possibility of contaminant-induced restructuring was excluded based on X-ray photoelectron spectroscopy (XPS) and low-energy He+ ion scattering (LEIS) measurements.

Original languageEnglish (US)
Pages (from-to)26424-26431
Number of pages8
JournalJournal of Physical Chemistry C
Volume121
Issue number47
DOIs
StatePublished - Nov 30 2017

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Energy(all)
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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    Balajka, J., Aschauer, U., Mertens, S. F. L., Selloni, A., Schmid, M., & Diebold, U. (2017). Surface Structure of TiO2 Rutile (011) Exposed to Liquid Water. Journal of Physical Chemistry C, 121(47), 26424-26431. https://doi.org/10.1021/acs.jpcc.7b09674