The effect of moisture on CO oxidation on Au/TiO2(110) model catalysts is investigated using temperature-programmed desorption and molecular beam reactive scattering under ultrahigh vacuum (UHV) conditions. Oxygen exchange is observed between adsorbed atomic oxygen and isotopically labeled water. Coadsorbed water (H218O) takes part in CO oxidation on Oa precovered Au/TiO2(110) model catalysts, leading to the formation of C16O18O and C16O 16O. The amount of C16O18O produced increases with increasing water coverages; however, the total amount of CO2 produced decreases. Although coadsorbed Oa and H2O have a minimal influence on the initial adsorption probability of CO, the total uptake of CO decreases as H2O coverages increase. Interestingly, the adsorption of water induces desorption of predeposited molecularly chemisorbed O2. Thus, adsorbed water slightly inhibits CO oxidation on atomic oxygen precovered Au/TiO2(110) model catalysts under UHV conditions.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films