Effect of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation

This study was focused on the influence of active oxygen on the performance of Pt/CeO2 catalysts for CO oxidation. A series of CeO2 supports with different contents of active oxygen were obtained by adding surfactant at different synthesis steps. 0.25 wt% Pt was loaded on these CeO2 supports by incipient-wetness impregnation methods. The catalysts were characterized by N-2 adsorption, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), H-2 temperature-programmed reduction (H-2-TPR), dynamic oxygen storage capacity (DOSC) and in-situ DRIFTS technologies. For S-f supports, the surfactant was added into the solution before spray-drying in the synthesis process, which facilitates more active oxygen formation on the surface of CeO2. After loading Pt, the more active oxygen on CeO2 contributes to dispersing Pt species and enhancing the CO oxidation activity. As for the aged samples, Pt-R-h shows the highest activity above 190 degrees C because of the presence of more partly oxidized Ptdthorn species. Thus the activity is also influenced by the states of Pt and the Pt delta+ species may contribute to the high activity at elevated temperature. (C) 2018 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.