In this work, Mn(CeZr)Ox was synthesized by using chelation-induced synergistic self-assembly strategy for the combustion of toluene. The physicochemical properties of the synthesized catalysts were characterized by XRD, ICP-MS, SEM, TEM, XPS and N2 sorption. The Mn(CeZr)Ox catalyst with T90 = 225 °C exhibited improved catalytic performance than the original MnOx catalyst (T90 = 260 °C) and had significant low-temperature activity. The relationship between catalyst activity and structure was analyzed. By substituting Ce and Zr elements into the hollow microspheres of MnO2, oxygen vacancies were produced. The main factors affecting the catalytic activity of the catalyst and the reason why it remained high catalytic activity after a long period of hydrothermal treatment were discussed. After hydrothermal aging, the original pore structure of Mn(CeZr)Ox catalyst collapsed and the specific surface area decreased, but the overall crystallinity of the catalyst increased and the content of oxygen species in the lattice increased. The distribution of Mn and oxygen species on the catalyst surface changed significantly after hydrothermal treatment. The appropriate ratio of Mn4+ to Mn3+ and the ratio of lattice oxygen to adsorbed oxygen species are beneficial to the redox reaction cycle.
Keywords: Catalytic oxidation; Chelation induction; Hydrothermal aging; Metal oxide catalyst; Toluene.
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