First layer water phases on anatase TiO2(101)
(2018) In Surface Science 674. p.25-31- Abstract
The anatase TiO2(101) surface and its interaction with water is an important topic in oxide surface chemistry. Firstly, it benchmarks the properties of the majority facet of TiO2 nanoparticles and, secondly, there is a controversy as to whether the water molecule adsorbs intact or deprotonates. We have addressed the adsorption of water on anatase TiO2(101) by synchrotron radiation photoelectron spectroscopy. Three two-dimensional water structures are found during growth at different temperatures: at 100 K, a metastable structure forms with no hydrogen bonding between the water molecules. In accord with prior literature, we assign this phase to chains of disordered molecules. Growth 160 K results in a... (More)
The anatase TiO2(101) surface and its interaction with water is an important topic in oxide surface chemistry. Firstly, it benchmarks the properties of the majority facet of TiO2 nanoparticles and, secondly, there is a controversy as to whether the water molecule adsorbs intact or deprotonates. We have addressed the adsorption of water on anatase TiO2(101) by synchrotron radiation photoelectron spectroscopy. Three two-dimensional water structures are found during growth at different temperatures: at 100 K, a metastable structure forms with no hydrogen bonding between the water molecules. In accord with prior literature, we assign this phase to chains of disordered molecules. Growth 160 K results in a metastable structure with expressed hydrogen bonding between the water molecules. At 190 K, the water molecules become disordered as the thermal energy is too high and hence the hydrogen bonds break. The result is a structure with isolated monomers. Partial dissociation is observed for all three growths, with the molecular state only slightly favored in energy (20–40 meV) over the dissociated state. Heating of a thick film leads to more dissociation compared to a bilayer, when formed at 100 K. Thus, extending the water network facilitates proton transport and hence dissociation. The results reconcile apparent conflicting experimental results previously obtained by scanning tunneling microscopy (STM) and core level photoelectron spectroscopy.
(Less)
- author
- Schaefer, A. LU ; Lanzilotto, V. ; Cappel, U. ; Uvdal, P. LU ; Borg, A. and Sandell, A.
- organization
- publishing date
- 2018
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Anatase, Dissociation, Metal oxides, Monolayer, Photoelectron spectroscopy, TiO, Water adsorption
- in
- Surface Science
- volume
- 674
- pages
- 7 pages
- publisher
- Elsevier
- external identifiers
-
- scopus:85053325394
- ISSN
- 0039-6028
- DOI
- 10.1016/j.susc.2018.03.019
- language
- English
- LU publication?
- yes
- id
- 5c0da500-6cf8-4602-972e-2d78af3ead36
- date added to LUP
- 2022-03-29 15:05:33
- date last changed
- 2022-04-21 23:21:21
@article{5c0da500-6cf8-4602-972e-2d78af3ead36,
abstract = {{<p>The anatase TiO<sub>2</sub>(101) surface and its interaction with water is an important topic in oxide surface chemistry. Firstly, it benchmarks the properties of the majority facet of TiO<sub>2</sub> nanoparticles and, secondly, there is a controversy as to whether the water molecule adsorbs intact or deprotonates. We have addressed the adsorption of water on anatase TiO<sub>2</sub>(101) by synchrotron radiation photoelectron spectroscopy. Three two-dimensional water structures are found during growth at different temperatures: at 100 K, a metastable structure forms with no hydrogen bonding between the water molecules. In accord with prior literature, we assign this phase to chains of disordered molecules. Growth 160 K results in a metastable structure with expressed hydrogen bonding between the water molecules. At 190 K, the water molecules become disordered as the thermal energy is too high and hence the hydrogen bonds break. The result is a structure with isolated monomers. Partial dissociation is observed for all three growths, with the molecular state only slightly favored in energy (20–40 meV) over the dissociated state. Heating of a thick film leads to more dissociation compared to a bilayer, when formed at 100 K. Thus, extending the water network facilitates proton transport and hence dissociation. The results reconcile apparent conflicting experimental results previously obtained by scanning tunneling microscopy (STM) and core level photoelectron spectroscopy.</p>}},
author = {{Schaefer, A. and Lanzilotto, V. and Cappel, U. and Uvdal, P. and Borg, A. and Sandell, A.}},
issn = {{0039-6028}},
keywords = {{Anatase; Dissociation; Metal oxides; Monolayer; Photoelectron spectroscopy; TiO; Water adsorption}},
language = {{eng}},
pages = {{25--31}},
publisher = {{Elsevier}},
series = {{Surface Science}},
title = {{First layer water phases on anatase TiO<sub>2</sub>(101)}},
url = {{http://dx.doi.org/10.1016/j.susc.2018.03.019}},
doi = {{10.1016/j.susc.2018.03.019}},
volume = {{674}},
year = {{2018}},
}