AVS 53rd International Symposium
    Surface Science Wednesday Sessions
       Session SS2-WeM

Paper SS2-WeM10
Alane Formation on Al(111)

Wednesday, November 15, 2006, 11:00 am, Room 2004

Session: Electronic and Vibrational Excitations and Dynamics
Presenter: J.-F. Veyan, Rutgers University
Authors: J.-F. Veyan, Rutgers University
Y.J. Chabal, Rutgers University
Correspondent: Click to Email
Complex metal hydrides, such as NaAlH@sub4@,are candidates for hydrogen storage because they can reversibly release and recapture hydrogen under near ambient conditions. Surface processes in the hydrogen storage reaction in NaAlH@sub4@, starting from a depleted phase consisting of NaH and metallic Al, and proceeding via cryolite Na@sub3@AlH@sub6@ to the hydrogen-rich NaAlH@sub4@, are considered as the basis for understanding reversible hydrogen storage in the chosen prototype system. Since metallic Al, particularly when doped with other metals, appear key to H@sub2@ dissociation, we have undertaken a comprehensive study of H interaction with Al(111) and Ti-doped Al(111) surfaces to better understand the atomic scale mechanisms underlying this reversible hydrogen storage behavior. Molecular hydrogen does not dissociate on pure, clean Al surfaces. However, below the desorption threshold of ~280K, atomic H interacts strongly with Al by extracting step and terrace atoms to form surface alane (AlH@sub3@). Using IR spectroscopy, we have studied Al(111) after atomic H exposure and of Ti-doped Al(111) after H@sub2@ exposure. The resulting spectra show the presence of alanes, characterized by terminal Al-H and bridging Al-H-Al termination.@footnote 1,2,3@ Preliminary experiments indicate that H@sub2@ does dissociate on Ti-doped Al(111) surfaces, again forming alanes. The evolution of these oligomers as a function of substrate temperature will be discussed. @FootnoteText@@footnote 1@ C. Liang, R. Davy, H.F. Schaefer III, Chem. Phys. Lett. 159 (1989) 393. @footnote 2@ B.J. Duke, C. Liang, H.F. Schaeffer III, J. Am. Chem. Soc. 113 (1991) 2884. @footnote 3@ M. Shen, C. Liang, H.F. Schaefer III, Chem. Phys. 171 (1993) 325.