AVS 45th International Symposium
    Surface Science Division Thursday Sessions
       Session SS2-ThM

Invited Paper SS2-ThM1
Coadsorption Studies with Water: a Small Step Toward Understanding the Surface Chemical and Photochemical Properties of TiO@sub 2@

Thursday, November 5, 1998, 8:20 am, Room 309

Session: Oxide Surface Chemistry
Presenter: M.A. Henderson, Pacific Northwest National Laboratory@footnote 1@
Authors: M.A. Henderson, Pacific Northwest National Laboratory@footnote 1@
W.S. Epling, Pacific Northwest National Laboratory
C.H.F. Peden, Pacific Northwest National Laboratory
U. Diebold, Tulane University
Correspondent: Click to Email
Perhaps the most prevalent surface species on an oxide surface in any environment or application is water. Depending on the conditions this molecule can be present on oxide surfaces as dissociation fragments (hydroxyls), as molecularly adsorbed species, as a thin physisorbed layer or as a bulk solid/liquid interface. The prevalence of water at oxide surfaces may lead one to think that its role in surface chemistry on oxides, such as TiO@sub 2@, is mostly that of a spectator. Although this appears to be the case in the UHV surface chemistry of more strongly bound species such as formate or methanol on TiO@sub 2@(110), water has a significant influence on more weakly bound species. This influence leads to interesting chemistry if defect sites are present. After a brief description of the properties of water on TiO@sub 2@(110), results will be presented for the formation of bicarbonate from coadsorption of water and carbon dioxide at oxygen vacancies, and for the reaction of molecular oxygen with bridging hydroxyl groups at oxygen vacancies. These results provide insights into photochemical oxidation and reduction processes occurring on titanium dioxide.@footnote 2@ @FootnoteText@ @footnote 1@PNNL is a multiprogram national laboratory operated for the U.S. DOE by Battelle Memorial Institute under Contract DE-AC06-76RLO 1830.) 2. This work was funded by the DOE office of Basic Energy Sciences, Materials Sciences, and the DOE Environmental Management Science Program.