Desorption kinetics of H2 from Al(100), Al(110) and Al(111)

Hydrogen desorption from three different aluminum single crystal surfaces [(100), (110), and (111)] has been studied using angle resolved thermal desorption spectroscopy. Adsorption of hydrogen was facilitated using dissociated atomic hydrogen from a hot Knudsen cell. Saturation coverages between 1....

Full description

Saved in:
Bibliographic Details
Published in:Surface science 1991-07, Vol.251-252, p.886-890
Main Authors: Winkler, A., Požgainer, G., Rendulic, K.D.
Format: Article
Language:English
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Hydrogen desorption from three different aluminum single crystal surfaces [(100), (110), and (111)] has been studied using angle resolved thermal desorption spectroscopy. Adsorption of hydrogen was facilitated using dissociated atomic hydrogen from a hot Knudsen cell. Saturation coverages between 1.3 and 2.4 monolayers have been obtained. The shape of the desorption spectra exhibits a zero order desorption mechanism for all three aluminum surfaces. This behavior can be explained using a model in which desorption is assumed to take place simultaneously from hydrogen lattice gas in equilibrium with a condensed two-dimensional phase. The angular distribution of the desorption probability for associatively desorbing H2 molecules exhibits a strongly forward focused function. The sharpest distribution is obtained for the (110) surface with D(φ) α cos20φ. This indicates a very high activation barrier for adsorption and desorption.
ISSN:0039-6028
1879-2758
DOI:10.1016/0039-6028(91)91118-H