AVS 45th International Symposium
    Surface Science Division Friday Sessions
       Session SS2-FrM

Paper SS2-FrM8
Coadsorption of Water and Hydrogen on Pt(110)

Friday, November 6, 1998, 10:40 am, Room 309

Session: Water and Ice Interfaces
Presenter: P. Blowers, University of Illinois, Urbana
Authors: P. Blowers, University of Illinois, Urbana
N. Chen, University of Illinois, Urbana
R. Masel, University of Illinois, Urbana
Correspondent: Click to Email
In previous papers, various investigators have discovered a new species when hydrogen and water coadsorb on various faces of platinum. However, the exact nature of the species is still in dispute. In this paper we combine high quality HREELS spectra with abinitio calculations to try to identify the species. The EELS spectrum of coadsorbed water an hydrogen shows peaks at 1180 and 3340 cm-1 which are not seen with water or hydrogen alone. The peaks shift with deuteration in a way expected for compound formation between water and hydrogen. Abinitio methods at the MP2/6-31G* level are used to identify the species. We have not found any (H2O)nH clusters, radical species or negative ions with vibrations near 1180 cm-1 However, cationic species e.g. [H3O]+, [H5O2]+, [H7O3]+ give vibrations in the right range. A detailed comparison of theory and experiment suggests that a number of hydrated ions form during the coadsorption process, with [H5O2]+, and [H7O3]+ being the most important.