Reaction of CO with molecularly chemisorbed oxygen on TiO2-supported gold nanoclusters

In this study we present results of an investigation into the reactivity of molecularly chemisorbed oxygen species on a Au/TiO2 model catalyst. We have previously shown that a Au/TiO2 model catalyst sample can be populated with both atomically and molecularly chemisorbed oxygen species following exposure to a radio frequency-generated oxygen plasma-jet. To test the reactivity of the molecularly chemisorbed oxygen species, we compare the CO2 produced from a sample that is populated with both oxygen species to the CO2 produced from a sample that has been given an identical exposure but has been cleared of molecularly chemisorbed oxygen employing collision-induced desorption. We observe that samples that are populated with both oxygen species consistently result in greater CO2 production. For the data presented in this paper, we observe a difference of 41% in the CO2 production. We interpret this result to indicate that molecularly chemisorbed oxygen can react directly with CO to form CO2.