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

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 quasi-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.