Effect of Pt Loading Methods of Pt/CeO2 Catalysts Derived from Ce-BTC as Support on Catalytic Oxidation of Toluene

Three Pt/CeO2 catalysts were prepared via thermal reduction with different Pt introduction sequences: impregnation (IM), reverse impregnation (RIM), and reduction–co-assembly (RCM). Their physicochemical properties and catalytic oxidation activity for toluene were compared over IM-prepared Ptpre/CeO2, RIM-prepared Pt/CeO2pre, and RCM-prepared Ptpre/CeO2pre. Different Pt loading methods affect the distribution, particle size, chemical state of Pt, and the metal–support interaction on the catalyst surface. Among them, the Ptpre/CeO2pre catalyst exhibits a high oxygen vacancy concentration and the best low-temperature reduction characteristics. Its high Ce3+/Ce4+ ratio, lattice oxygen content, and the content of Pt with active valence states (Pt0, Pt2+) are all conducive to the catalytic oxidation of toluene. The content of different valence states of Pt, dispersion degree, and cluster size of Pt on the catalyst, as well as oxygen vacancies and the valence state of Ce, were evaluated by XPS, Raman, H2-TPR, in situ infrared, TEM, and N2 adsorption–desorption tests, clarifying the reasons for the high activity of the catalyst. This provides an experimental basis and contributes strategies for the development of noble metal-loaded oxide catalysts prepared from metal–organic frameworks as precursors.