Charge Trapping at the Step Edges of TiO2 Anatase (101)

Authors

  • Martin Setvin,

    1. Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)
    2. Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnicka 10, 16200 (Czech Republic)
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  • Xianfeng Hao,

    1. Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)
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  • Benjamin Daniel,

  • Jiri Pavelec,

    1. Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)
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  • Zbynek Novotny,

    1. Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)
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  • Gareth S. Parkinson,

    1. Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)
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  • Michael Schmid,

    1. Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)
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  • Georg Kresse,

    1. Faculty of Physics and Center for Computational Materials Science, Universität Wien, Sensengasse 8/12, A-1090 Wien (Austria)
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  • Cesare Franchini,

    1. Faculty of Physics and Center for Computational Materials Science, Universität Wien, Sensengasse 8/12, A-1090 Wien (Austria)
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  • Ulrike Diebold

    Corresponding author
    1. Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)
    • Institut für Angewandte Physik, Technische Universität Wien, Wiedner Hauptstrasse 8-10/134, 1040 Vienna (Austria)===

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  • The work was supported by the Austrian Science Fund (FWF; project F45) and the ERC grant “Oxide Surfaces”. We thank HZB for the allocation of synchrotron radiation beamtime.

Abstract

A combination of photoemission, atomic force, and scanning tunneling microscopy/spectroscopy measurements shows that excess electrons in the TiO2 anatase (101) surface are trapped at step edges. Consequently, steps act as preferred adsorption sites for O2. In density functional theory calculations electrons localize at clean step edges, this tendency is enhanced by O vacancies and hydroxylation. The results show the importance of defects for the wide-ranging applications of titania.

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