Tuning the Metal–Support Interaction by Modulating CeO₂ Oxygen Vacancies to Enhance the Toluene Oxidation Activity of Pt/CeO₂ Catalysts

Abstract

In this research, a range of Pt/CeO₂ catalysts featuring varying Pt-O-Ce bond contents were developed by modulating the oxygen vacancies of the CeO₂ support for toluene abatement. The Pt/CeO₂-HA catalyst generated a maximum quantity of Pt-O-Ce bonds (possessed the strongest metal-support interaction), as evidenced by the visible Raman results, which demonstrated outstanding toluene catalytic performance. Additionally, the UV Raman results revealed that the strong metal-support interaction stimulated a substantial increase in oxygen vacancies, which could facilitate the activation of gaseous oxygen to generate abundant reactive oxygen species accumulated on the Pt/CeO₂-HA catalyst surface, a conclusion supported by the H₂-TPR, XPS, and toluene-TPSR results. Furthermore, the results from <i>quasi-</i>in situ XPS, in situ DRIFTS, and DFT indicated that the Pt/CeO₂-HA catalyst with a strong metal-support interaction led to improved mobility of reactive oxygen species and lower oxygen activation energies, which could transfer a large number of activated reactive oxygen species to the reaction interface to participate in the toluene oxidation, resulting in the relatively superior catalytic performance. The approach of tuning the metal-support interaction of catalysts offers a promising avenue to develop highly active catalysts for toluene degradation.