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MnOx samples were prepared and applied to the catalytic combustion of toluene. The results indicated that the KMnO4 content was important to the catalytic performance. Cat‐0.2 (0.2 g KMnO4) possessed the best catalytic performance, and more than 90% of toluene conversion was 255°C. Moderate amounts of KMnO4 facilitated the generation of mixed crystalline phases and structural defects, which led to the generation of more oxygen vacancies. In addition, the Cat‐0.2 possessed high contents of Oads/(Oads + Olatt) and Mn3+/(Mn3+ + Mn4+), which promoted the emergence‐annihilation cycle of oxygen vacancies and facilitated the reaction process of toluene. The reaction pathway of toluene was investigated via in situ DRIFTS, in which the by‐products included benzyl alcohol, benzaldehyde, benzoate, maleic anhydride, and short‐chain carbonate. Among them, benzoate was the main intermediate in the catalytic oxidation process of toluene. [ABSTRACT FROM AUTHOR]

A series of Ce-M(Cu, Co and Fe) catalysts were synthesized via sol–gel methods. In situ DRIFTS was introduced to explored the process of toluene degradation, confirming oxygen vacancies played an important role. [Display omitted] • Ce-Cu sample exhibited best catalytic activity and stability for toluene oxidation. • Superb activity was attributed to high Ce3+/ Ce4+ and high O ads /O latt. • The oxygen vacancies were modulated by different metal doping. • Benzoic acid was key intermediates in toluene catalysis by in situ DRIFT analysis. A series of CeO 2 samples modified with various metals M (M = Cu, Co and Fe) were synthesized via a simple sol–gel approach. The experimental results showed that there were significant differences in the catalytic activities between different metal-doped Ce-based catalysts. The Ce-Cu sample possessed excellent catalytic activity at low temperatures, and 90 % conversion of toluene was at 255 ℃, which was due to the presence of ample oxygen vacancies (O v). Three degradation pathways for toluene oxidation were inferred based on the in situ DRIFTS. The Ce-Cu catalysts possessed abundant O v , which improved the conversion between O ads → O latt and the breakage of aromatic rings, thus reducing the production of intermediates. The Ce-Co and Ce-Fe catalysts owned few amounts of O v species, leading to an extensive amount of by-products. Furthermore, the loss of active sites inhibited the reaction rate, causing the inferior catalytic performance of the Ce-Co and Ce-Fe samples. [ABSTRACT FROM AUTHOR]