Insight into the transient inactivation effect on Au/TiO2 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/TiO2. A pronounced transient inactivation effect likely due to a structural change of Au/TiO2 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/TiO2 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. A molecular-level understanding of the Au-catalyzed CO oxidation on a fast time-resolved scale is still lacking. Here the authors monitor the rapid dynamic changes during CO oxidation over Au/TiO2 using in situ DRIFTS and UV-Vis spectroscopy, and reveal that the catalyst undergoes a surprising structural change at the beginning of the reaction.

Automated summary

In the CO oxidation reaction over Au/TiO2, a transient inactivation effect caused by structural change of Au/TiO2 is observed, which is affected by the ratio of CO and O-2 concentrations. The electronic properties of Au particles also change during the unstable state.