Elucidating the Oxygen Activation Mechanism on Ceria-Supported Copper-Oxo Species Using Time-Resolved X-ray Absorption Spectroscopy
We monitored the dynamic structure of the active sites in a catalyst containing highly dispersed copper-oxo species on ceria during low-temperature CO oxidation using time-resolved X-ray absorption spectroscopy. We quantitatively demonstrate that the CO oxidation mechanism below 90 °C involves an oxygen intermediate strongly bound to the active sites as well as the redox activity of Cu2+/Cu+ and Ce4+/Ce3+ couples.
Unlike the homogeneous Wacker process, the understanding of the mechanism of the heterogeneous system has long remained to be superficial. Here the authors investigated the mechanism of heterogeneous Wacker oxidation over Pd-Cu/zeolite Y through transient XAS coupled with kinetic studies and chemometric analysis.
V2O5/TiO2 SCR catalysts
An increased level of mechanistic information is obtained when Raman spectroscopy is combined with modulated excitation in the case of V-based catalysts used for SCR.
The combination of time-resolved XAS and transient experiments enables to capture an inhibition effect by NH3 on the rate-limiting re-oxidation of CuI at low temperature.
Time-resolved XAS is exploited to capture the dynamic local electronic and geometric structure of perovskite oxides under operando conditions.