Reactive Scattering of CO from an Oxygen-Atom-Covered Au/TiO₂ Model Catalyst

We present results of a reactive scattering study of CO from an oxygen-atom-covered Au/TiO 2 model catalyst. We studied the CO oxidation reaction with preadsorbed atomic oxygen over a surface temperature range from 65 to 250 K and observed CO 2 production at all temperatures studied from the gold-covered titania samples. No reaction is observed on the bare TiO 2 (i.e., no gold) at any of the temperatures studied. The CO oxidation reaction is observed to proceed on all gold coverages studied (0.25−30 ML) as well as on a nominally continuous gold film. Hence, we conclude that the reaction of an oxygen atom with CO is relatively particle size independent and even independent of the TiO 2 support and therefore not exclusive to the gold−titania interface, if oxygen atoms are preadsorbed prior to CO exposure.