Catalytic combustion of toluene performance over MnO_x catalysts: Effect of KMnO₄ content

Abstract

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.