Chemical composition and reactivity of water on clean and oxygen-covered Pd{1 1 1}

Title: Chemical composition and reactivity of water on clean and oxygen-covered Pd{1 1 1}
Creator: Gladys, M. J.; El Zein, A. A.; Mikkelsen, A.; Andersen, J. N.; Held, G.
Relation: Surface Science Vol. 602, Issue 22, p. 3540-3549
Publisher Link: http://dx.doi.org/10.1016/j.susc.2008.09.031
Publisher: Elsevier
Resource Type: journal article
Date: 2008
Description: The chemical composition and dissociation behaviour of water adsorbed on clean and oxygen pre-covered Pd{1 1 1} was studied using high-resolution time-resolved and temperature-programmed X-ray photoelectron spectroscopy. We find that water remains intact at all temperatures up to desorption on the clean surface and at high oxygen coverage(0.69 ML) when a surface oxide is formed. The highest desorption peaks occur at 163 K from the clean surface and at 172 K from the surface oxide. At the intermediate coverage of 0.20 ML oxygen reacts with coadsorbed water at 155 K, to generate a mixed H₂O/OH layer exhibiting a (√3 x √3)R30°d iffraction pattern, which is stable up to 177 K. The measured ratio between intact water and the hydroxyl species in this layer varies between 1.5 and 2 depending on temperature.
Subject: palladium; water; oxygen; photoelectron spectroscopy; chemisorption; catalysis
Identifier: uon:5309
Identifier: http://hdl.handle.net/1959.13/43182
Identifier: ISSN:0039-6028
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