Insight into the transient inactivation effect on Au/TiO(2) catalyst by in-situ DRIFT and UV–vis spectroscopy

Au catalysts have drawn broad attention for catalytic CO oxidation. However, a molecular-level understanding of the reaction mechanism on a fast time-resolved scale is still lacking. Herein, we apply in situ DRIFTS and UV-Vis spectroscopy to monitor the rapid dynamic changes during CO oxidation over Au/TiO(2). A pronounced transient inactivation effect likely due to a structural change of Au/TiO(2) induced by the reactants (CO and O(2)) is observed at the beginning of the reaction. The transient inactivation effect is affected by the ratio of CO and O(2) concentrations. More importantly, during the unstable state, the electronic properties of the Au particles change, as indicated by the shift of the CO stretching vibration. UV-Vis spectroscopy corroborates the structure change of Au/TiO(2) surface induced by the reactants, which leads to a weakening of the Au catalyst’s ability to be oxidized (less O(2) adsorption), resulting in the transient inactivation effect.