AVS 45th International Symposium
    Surface Science Division Monday Sessions
       Session SS-MoP

Paper SS-MoP19
Reactivity of Hydrogen with Fluorinated LaNi@sub5@

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Surface Science Division Poster Session
Presenter: A.R. Layson, Iowa State University
Authors: A.R. Layson, Iowa State University
C.J. Jenks, Iowa State University
Correspondent: Click to Email
Much interest has been shown in hydrogen storage alloys as possible replacements for cadmium-based rechargeable batteries. Recent work under atmospheric conditions has shown that fluorination of the hydrogen storage material LaNi@sub 5@ substantially improves its ability to adsorb and subsequently desorb hydrogen. We report on studies aimed at understanding the effects of fluorination of LaNi@sub 5@. These are conducted in an ultrahigh vacuum environment using a single crystal of LaNi@sub 5@. Despite LaNi@sub 5@ being notoriously difficult to clean we have developed a method of cleaning which leaves less than 2% impurities at the surface. We follow surface compositional changes with Auger electron spectroscopy and hydrogen release with thermal desorption spectroscopy; these studies are the first such studies on LaNi@sub 5@. We compare results for D@sub 2@ adsorption/desorption on the clean surface to that of an oxidized surface and a surface that has been fluorinated after oxidation. We find that fluorination of the oxidized surface results in a low temperature channel for D@sub 2@ evolution not present on the surface that has only been oxidized. In addition the fluorinated surface enhances the amount of D@sub 2@ dissociation possible.