Münster 1997 – wissenschaftliches Programm
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O: Oberflächenphysik
O 22: POSTER II
O 22.38: Poster
Mittwoch, 19. März 1997, 14:15–15:45, AULA
CO OXIDATION ON AG(001) BY O2 OR O: A HREELS STUDY. — •U. Burghaus1, L. Vattuone2, P. Gambardella2, and M. Rocca2 — 1UC Santa Barbara, Dept.Chem.Eng.II, CA 93106-5080, USA — 2Dipartimento di Fisica, via Dodecaneso 33, 16146 Genova, Italy
The interaction of CO with O2ad and Oad was investigated on Ag(001) by HREELS dosing the reactants with a molecular beam. We find that under our best clean working conditions and at a surface temperature of 100K, CO removes O2ad with a much lower reaction probability than for Ag(110) (see. Surf.Sci. 364 (1996) 109). For Oad the removal rate was smaller than experimental sensitivity. Impurities (such as water) affect however strongly the reaction probability for CO oxidation by both O and O2. The reaction mechanism is LH-type as proved by the temperature dependence. CO can be stabilized at the surface by impurities. CO removed then Oad above 160 K.