Abstract
Using high-resolution scanning tunneling microscopy (STM), we have studied the oxidation of rutile TiO 2(1 1 0)–(1 × 1) surfaces with H ad 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 backfilling 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 TiO 2(1 1 0) surfaces with O ot adatoms (o-TiO 2). It is certain that o-TiO 2(1 1 0) surfaces prepared according to this recipe do not have any residual surface O vacancies. This contradicts the situation when oxidizing reduced TiO 2(1 1 0) surfaces with O vacancies, where some O vacancies persist.
| Original language | English |
|---|---|
| Journal | Surface Science |
| Volume | 666 |
| Pages (from-to) | 113-122 |
| Number of pages | 10 |
| ISSN | 0039-6028 |
| DOIs | |
| Publication status | Published - Dec 2017 |
Keywords
- CHEMISTRY
- ELECTRON
- H-ad species (OHbr groups)
- H2O
- O-2 DISSOCIATION
- O-ot adatoms
- OH GROUPS
- OHt groups
- OXYGEN ADATOMS
- REDUCED RUTILE TIO2(110)
- Rutile TiO2(110)
- SCANNING-TUNNELING-MICROSCOPY
- Scanning tunneling microscopy (STM)
- TIO2 PHOTOCATALYSIS
- TITANIUM-DIOXIDE
- WATER