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Local ordering and electronic signatures of submonolayer water on anatase TiO2(101)

Nature Materials volume 8, pages 585589 (2009) | Download Citation

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Abstract

The interaction of water with metal oxide surfaces is of fundamental importance to various fields of science, ranging from geophysics to catalysis and biochemistry1,2,3,4. In particular, the discovery that TiO2 photocatalyses the dissociation of water5 has triggered broad interest and intensive studies of water adsorption on TiO2 over decades6. So far, these studies have mostly focused on the (110) surface of the most stable polymorph of TiO2, rutile, whereas it is the metastable anatase form that is generally considered photocatalytically more efficient. The present combined experimental (scanning tunnelling microscopy) and theoretical (density functional theory and first-principles molecular dynamics) study gives atomic-scale insights into the adsorption of water on anatase (101), the most frequently exposed surface of this TiO2 polymorph. Water adsorbs as an intact monomer with a computed binding energy of 730 meV. The charge rearrangement at the molecule–anatase interface affects the adsorption of further water molecules, resulting in short-range repulsive and attractive interactions along the [010] and directions, respectively, and a locally ordered (2×2) superstructure of molecular water.

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References

  1. 1.

    The interaction of water with solid surfaces: Fundamental aspects revisited. Surf. Sci. Rep. 46, 1–308 (2002).

  2. 2.

    , , & Molecular structure of water at interfaces: Wetting at the nanometer scale. Chem. Rev. 106, 1478–1510 (2006).

  3. 3.

    & Oxide surfaces as environmental interfaces. Surf. Sci. Rep. 52, 63–161 (2003).

  4. 4.

    & The interaction of water with solid surfaces: Fundamental aspects. Surf. Sci. Rep. 7, 211–385 (1987).

  5. 5.

    & Electrochemical photolysis of water at a semiconductor electrode. Nature 238, 37–38 (1972).

  6. 6.

    The surface science of titanium dioxide. Surf. Sci. Rep. 48, 53–229 (2003).

  7. 7.

    , & Chemical reactions on rutile TiO2(110). Chem. Soc. Rev. 37, 2328–2353 (2008).

  8. 8.

    et al. Formation and splitting of paired hydroxyl groups on reduced TiO2(110). Phys. Rev. Lett. 96, 066107 (2006).

  9. 9.

    , , , & Imaging water dissociation on TiO2(110): Evidence for inequivalent geminate OH groups. J. Phys. Chem. B 110, 21840–21845 (2006).

  10. 10.

    , & Imaging water dissociation on TiO2(110). Phys. Rev. Lett. 87, 266103 (2001).

  11. 11.

    , , & Structure and energetics of water adsorbed at TiO2 anatase (101) and (001) surfaces. Phys. Rev. Lett. 81, 2954–2957 (1998).

  12. 12.

    & Vertical and lateral order in adsorbed water layers on anatase TiO2(101). Langmuir 20, 8379–8384 (2004).

  13. 13.

    , , & Short hydrogen bonds at the water/TiO2 (anatase) interface. J. Phys. Chem. C 112, 13579–13586 (2008).

  14. 14.

    , , & One step towards bridging the materials gap: Surface studies of TiO2 anatase. Catal. Today 85, 93–100 (2003).

  15. 15.

    , , & Steps on anatase TiO2(101). Nature Mater. 5, 665–670 (2006).

  16. 16.

    , , & Experimental investigation of the interaction of water and methanol with anatase-TiO2(101). J. Phys. Chem. B 107, 2788–2795 (2003).

  17. 17.

    , , , & Evidence for the predominance of subsurface defects on reduced anatase TiO2(101). Phys. Rev. Lett. 102, 106105 (2009).

  18. 18.

    et al. Novel water overlayer growth on Pd(111) characterized with scanning tunneling microscopy and density functional theory. Phys. Rev. Lett. 93, 116101 (2004).

  19. 19.

    & Ice nanoclusters at hydrophobic metal surfaces. Nature Mater. 6, 597–601 (2007).

  20. 20.

    & Unified approach for molecular dynamics and density-functional theory. Phys. Rev. Lett. 55, 2471–2474 (1985).

  21. 21.

    et al. Tuning the reactivity of oxide surfaces by charge-accepting adsorbates. Angew. Chem. Int. Ed. 46, 7315–7318 (2007).

  22. 22.

    , , , & Water diffusion and clustering on Pd(111). Science 297, 1850–1852 (2002).

  23. 23.

    et al. The properties of a two-dimensional water layer on MgO(001). Surf. Sci. 377–379, 634–638 (1997).

  24. 24.

    , & Observation of the dynamical change in a water monolayer adsorbed on a ZnO surface. Phys. Rev. Lett. 95, 136101 (2005).

  25. 25.

    & Exothermic water dissociation on the rutile TiO2(110) surface. Phys. Rev. B 72, 075439 (2005).

  26. 26.

    , & Composition, structure, and stability of the rutile TiO2(110) surface: Oxygen depletion, hydroxylation, hydrogen migration, and water adsorption. Phys. Rev. B 79, 115410 (2009).

  27. 27.

    , & Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996).

  28. 28.

    Soft self-consistent pseudopotentials in a generalized eigenvalue formalism. Phys. Rev. B 41, 7892–7895 (1990).

  29. 29.

    , , & Quantum ESPRESSO v. 3.2.3, <>.

  30. 30.

    & Theory of the scanning tunneling microscope. Phys. Rev. B 31, 805–813 (1985).

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Acknowledgements

This work was supported by DoE award DE-FG02-05ER15702. We thank C. Di Valentin for participating in the early stages of this project and H. Cheng for the constant density STM program. A.T. thanks the UK’s Royal Society for financial support.

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    • Yunbin He

    Present address: Faculty of Materials Sciences and Engineering, Hubei University, No. 11 Xueyuan Road, Wuchang, Wuhan 430062, China

Affiliations

  1. Department of Physics, Tulane University, New Orleans, Louisiana 70118, USA

    • Yunbin He
    • , Olga Dulub
    •  & Ulrike Diebold
  2. Department of Chemistry and Materials Simulation Laboratory, University College London, London WC1H 0AJ, UK

    • Antonio Tilocca
  3. Department of Chemistry, Princeton University, Princeton, New Jersey 08544, USA

    • Annabella Selloni

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Correspondence to Yunbin He or Ulrike Diebold.

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DOI

https://doi.org/10.1038/nmat2466

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