A new recipe for preparing oxidized TiO2(110) surfaces: An STM study

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Using high-resolution scanning tunneling microscopy (STM), we have studied the oxidation of rutile TiO2(110)-(1x1) surfaces with Had species at room temperature. We followed the evolution of various stable species as function of the O-2 exposure, and the nature of the ultimately dominating species in the Ti troughs is described. When O-2 saturation was accomplished using a glass-capillary array doser, we found that on-top O (O-ot) adatoms are the predominant surface species. In contrast, when O-2 was supplied via backfilfing of the chamber the predominant surface species are tentatively assigned to terminal OH groups. We argue that unintended reactions with the chamber walls have a strong influence on the formed surface species, explaining scattered results in the literature. On the basis of our STM data we propose an alternative, easy way of preparing oxidized TiO2(110) surfaces with O-ot adatoms (o-TiO2). It is certain that o-TiO2(110) surfaces prepared according to this recipe do not have any residual surface O vacancies. This contradicts the situation when oxidizing reduced TiO2(110) surfaces with O vacancies, where some O vacancies persist. (C) 2017 Elsevier B.V. All rights reserved.

Original languageEnglish
JournalSurface Science
Volume666
Pages (from-to)113-122
Number of pages10
ISSN0039-6028
DOIs
Publication statusPublished - Dec 2017

    Research areas

  • Rutile TiO2(110), H-ad species (OHbr groups), O-ot adatoms, H2O, OHt groups, Scanning tunneling microscopy (STM), SCANNING-TUNNELING-MICROSCOPY, REDUCED RUTILE TIO2(110), TIO2 PHOTOCATALYSIS, TITANIUM-DIOXIDE, O-2 DISSOCIATION, OXYGEN ADATOMS, OH GROUPS, WATER, CHEMISTRY, ELECTRON

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