Invited Paper SS+NC-MoM7
Reactivity Trends in CO Oxidation from UHV to Elevated Pressures: Never Mind the Gap

Monday, October 20, 2008, 10:20 am, Room 208

CO oxidation on Ru, Pd, Rh, and Pt surfaces has been investigated between 10^-8 – 10 Torr and for a variety of temperatures and O₂/CO ratios. Polarization modulation reflectance absorption infrared spectroscopy (PM-RAIRS) was used to identify the CO coverage as a function of the reaction rate for a variety of conditions up to 10 Torr. For reaction pressures less than 10^-6 Torr, X-ray photoelectron spectroscopy (XPS) was used to measure the surface coverages of CO and O_ads. A clear continuum with respect to reaction rates, surface composition, and overall mechanism is apparent over the entire pressure range investigated, i.e. there is no evidence of a pressure gap.