| AVS 55th International Symposium & Exhibition | |
| Surface Science | Thursday Sessions |
| Session SS1+NC-ThA |
| Session: | Water-Surface Interactions |
| Presenter: | X. Deng, Lawrence Berkeley National Laboratory |
| Authors: | X. Deng, Lawrence Berkeley National Laboratory T. Herranz, Lawrence Berkeley National Laboratory C. Weis, Lawrence Berkeley National Laboratory H. Bluhm, Lawrence Berkeley National Laboratory M. Salmeron, Lawrence Berkeley National Laboratory |
| Correspondent: | Click to Email |
The initial stages of water condensation, approximately 6 molecular layers, on two oxide surfaces, Cu2O and Al2O3, have been investigated using ambient pressure x-ray photoelectron spectroscopy at relative humidity values (RH) from 0 to > 90%. Water adsorbs first dissociatively on oxygen vacancies producing adsorbed hydroxyl groups in a stoichiometric reaction: Olattic + Vacancies + H2O = 2OH. The reaction is completed at ~ 1% RH and is followed by adsorption of molecular water. The thickness of the water film grows with increasing RH. The first monolayer is completed at ~ 15% RH on both oxides and is followed by a second layer at 35-40% RH. At 90% RH, about 6 layers of H2O film have been formed on Al2O3. The wetting process and the essential role of OH on oxide surfaces will also be discussed.