Goodacre, D;
Blum, M;
Buechner, C;
Hoek, H;
Gericke, SM;
Jovic, V;
Franklin, JB;
... Smith, KE; + view all
(2020)
Water adsorption on vanadium oxide thin films in ambient relative humidity.
Journal of Chemical Physics
, 152
(4)
, Article 044715. 10.1063/1.5138959.
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Abstract
In this work, ambient pressure x-ray photoelectron spectroscopy (APXPS) is used to study the initial stages of water adsorption on vanadium oxide surfaces. V 2p, O 1s, C 1s, and valence band XPS spectra were collected as a function of relative humidity in a series of isotherm and isobar experiments. Experiments were carried out on two VO2 thin films on TiO2 (100) substrates, prepared with different surface cleaning procedures. Hydroxyl and molecular water surface species were identified, with up to 0.5 ML hydroxide present at the minimum relative humidity, and a consistent molecular water adsorption onset occurring around 0.01% relative humidity. The work function was found to increase with increasing relative humidity, suggesting that surface water and hydroxyl species are oriented with the hydrogen atoms directed away from the surface. Changes in the valence band were also observed as a function of relative humidity. The results were similar to those observed in APXPS experiments on other transition metal oxide surfaces, suggesting that H2O–OH and H2O–H2O surface complex formation plays an important role in the oxide wetting process and water dissociation. Compared to polycrystalline vanadium metal, these vanadium oxide films generate less hydroxide and appear to be more favorable for molecular water adsorption.
| Type: | Article |
|---|---|
| Title: | Water adsorption on vanadium oxide thin films in ambient relative humidity |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1063/1.5138959 |
| Publisher version: | https://doi.org/10.1063/1.5138959 |
| Language: | English |
| Additional information: | This is the published version of record. For information on re-use, please refer to the publisher’s terms and conditions. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10097197 |
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