HREELS study of CO oxidation on Ag(001) by O2 or O

The interaction of CO with molecularly and atomically bonded oxygen was investigated on Ag(001) by HREELS, dosing the reactants with a supersonic molecular beam, We rind that under our best clean working conditions and at a surface temperature of 100 K, CO removes chemisorbed dioxygen with a much lower reaction probability than for Ag(110). For dissociatively chemisorbed oxygen the removal rate was smaller than the experimental sensitivity both at 100 and 300 K. However, impurities strongly affect the reaction probability for CO oxidation by both O and O-2. The reaction mechanism is of the Langmuir-Hinshelwood type as proved by the temperature dependence. CO can be stabilized at the surface under special conditions for which no extra HREELS peaks are observed. CO removed then atomically adsorbed O above 160 K.

The interaction of CO with molecularly and atomically bonded oxygen was investigated on Ag(001) by HREELS, dosing the reactants with a supersonic molecular beam. We find that under our best clean working conditions and at a surface temperature of 100 K, CO removes chemisorbed dioxygen with a much lower reaction probability than for Ag(110). For dissociatively chemisorbed oxygen the removal rate was smaller than the experimental sensitivity both at 100 and 300 K. However, impurities strongly affect the reaction probability for CO oxidation by both O and O2. The reaction mechanism is of the Langmuir-Hinshelwood type as proved by the temperature dependence. CO can be stabilized at the surface under special conditions for which no extra HREELS peaks are observed. CO removed then atomically adsorbed O above 160 K. © 1997 Elsevier Science B.V. All rights reserved.