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Defect-Induced Water Bilayer Growth on Anatase TiO2(101)

Schaefer, A. LU ; Lanzilotto, V.; Cappel, U. B.; Uvdal, P. LU ; Borg, A. and Sandell, A. (2018) In Langmuir 34(37). p.10856-10864
Abstract

Preparing an anatase TiO2(101) surface with a high density of oxygen vacancies and associated reduced Ti species in the near-surface region results in drastic changes in the water adsorption chemistry compared to adsorption on a highly stoichiometric surface. Using synchrotron radiation excited photoelectron spectroscopy, we observe a change in the water growth mode, from layer-by-layer growth on the highly stoichiometric surface to bilayer growth on the reduced surface. Furthermore, we have been able to observe Ti3+ enrichment at the surface upon water adsorption. The Ti3+ enrichment occurs concomitant with effective water dissociation into hydroxyls with a very high thermal stability. The water bilayer... (More)

Preparing an anatase TiO2(101) surface with a high density of oxygen vacancies and associated reduced Ti species in the near-surface region results in drastic changes in the water adsorption chemistry compared to adsorption on a highly stoichiometric surface. Using synchrotron radiation excited photoelectron spectroscopy, we observe a change in the water growth mode, from layer-by-layer growth on the highly stoichiometric surface to bilayer growth on the reduced surface. Furthermore, we have been able to observe Ti3+ enrichment at the surface upon water adsorption. The Ti3+ enrichment occurs concomitant with effective water dissociation into hydroxyls with a very high thermal stability. The water bilayer on the reduced surface is thermally more stable than that on the stoichiometric surface, and it is more efficient in promoting further water dissociation upon heating. The results thus show how the presence of subsurface defects can alter the wetting mechanism of an oxide surface.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
34
issue
37
pages
9 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85053295359
  • scopus:85053564157
ISSN
0743-7463
DOI
10.1021/acs.langmuir.8b01925
language
English
LU publication?
yes
id
35dcd5f0-6a8f-4fbb-8355-07f528fc5067
date added to LUP
2018-10-11 08:21:25
date last changed
2019-02-20 11:30:58
@article{35dcd5f0-6a8f-4fbb-8355-07f528fc5067,
  abstract     = {<p>Preparing an anatase TiO<sub>2</sub>(101) surface with a high density of oxygen vacancies and associated reduced Ti species in the near-surface region results in drastic changes in the water adsorption chemistry compared to adsorption on a highly stoichiometric surface. Using synchrotron radiation excited photoelectron spectroscopy, we observe a change in the water growth mode, from layer-by-layer growth on the highly stoichiometric surface to bilayer growth on the reduced surface. Furthermore, we have been able to observe Ti<sup>3+</sup> enrichment at the surface upon water adsorption. The Ti<sup>3+</sup> enrichment occurs concomitant with effective water dissociation into hydroxyls with a very high thermal stability. The water bilayer on the reduced surface is thermally more stable than that on the stoichiometric surface, and it is more efficient in promoting further water dissociation upon heating. The results thus show how the presence of subsurface defects can alter the wetting mechanism of an oxide surface.</p>},
  author       = {Schaefer, A. and Lanzilotto, V. and Cappel, U. B. and Uvdal, P. and Borg, A. and Sandell, A.},
  issn         = {0743-7463},
  language     = {eng},
  number       = {37},
  pages        = {10856--10864},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Defect-Induced Water Bilayer Growth on Anatase TiO<sub>2</sub>(101)},
  url          = {http://dx.doi.org/10.1021/acs.langmuir.8b01925},
  volume       = {34},
  year         = {2018},
}