Insights into Different Reaction Behaviors of Propane and CO Oxidation over Pt/CeO2 and Pt/Nb2O5: The Crucial Roles of Support Properties

Pt/CeO2 and Pt/Nb2O5 catalysts were employed to catalyze CO and propane oxidation. It was found that the Pt/CeO2 catalyst was more active than the Pt/Nb2O5 catalyst for CO oxidation, while it was less active in propane oxidation. The different behaviors were closely related to the nature of the support, which affected the properties of the active Pt species as well as the reaction pathways. For CO oxidation, the reaction took place at the Pt-CeO2 interface of the Pt/CeO2 catalyst. The facile activation of oxygen species on the CeO2 with abundant oxygen vacancies accounted for its high activity, while the competitive adsorption of CO and O-2 on the surface Pt atoms led to a strong inhibiting role of oxygen on the reactivity, which was indicated by a negative reaction order of oxygen on the Pt/Nb2O5 catalyst. For the propane oxidation, as metallic Pt species were beneficial for the activation of C-H bond in propane, the high concentration of metallic Pt species in the Pt/Nb2O5 induced by the stabilizing effect of surface acidity of the Nb2O5 support was responsible for its higher activity compared to the Pt/CeO2 with oxidized Pt species.

Automated summary

The Pt/CeO2 and Pt/Nb2O5 catalysts exhibit different activity in CO and propane oxidation, which is attributed to the different properties of the support affecting the active Pt species and reaction pathways. The high activity of Pt/CeO2 for CO oxidation is due to the facile activation of oxygen species on CeO2, while the high activity of Pt/Nb2O5 for propane oxidation is attributed to the high concentration of metallic Pt species induced by the stabilizing effect of surface acidity of Nb2O5 support.