Catalytic Oxidation of Toluene over CoMnOx/SBA-15 Catalyst: Promoting Effect of the Interaction Between Metal Active Components and the Support

For supported catalysts, the interaction between metal active components and the support plays a crucial role in modifying catalyst properties, such as active sites and oxygen vacancies. Herein, a series of CoMnOx/SBA-15 (Santa Barbara Amorphous-15) catalysts were prepared for catalytic oxidation of toluene, in which the support properties were tailored by varying the hydrothermal crystallization time. The results revealed that subtle changes in support properties could lead to modifications of the supported active component. CM-48 (crystallization time of 48 h) exhibited the optimal low-temperature activity with T90 of 234 °C and good stability for the catalytic oxidation of toluene. The improved performance was attributed to the enhancement of redox properties, abundant oxygen vacancies, and high mobility of lattice oxygen species resulting from the strong interaction between the active components and the support. Furthermore, the reaction mechanism was explored via in situ DRIFTS (Diffuse Reflectance Infrared Fourier Transform Spectroscopy), confirming that both surface-adsorbed oxygen and lattice oxygen served as active oxygen species participating in toluene oxidation, with surface-adsorbed oxygen being particularly favorable for the consumption of key intermediates. This work will guide the design of supported catalysts in practical applications for eliminating VOCs.