High-efficiency non-thermal plasma-catalysis of cobalt incorporated mesoporous MCM-41 for toluene removal

The destruction of low concentrations of toluene in air streams using a non-thermal plasma catalysis system has been investigated in this study. A series of highly active cobalt incorporated MCM-41 (Co-MCM-41) catalysts were synthesized by a hydrothermal method. For comparison, cobalt-impregnated MCM-41 (Co-MCM-41_imp) catalysts were prepared via an impregnation method. The synthesized samples were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms, UV–vis diffuse reflection spectrum (UV–vis DRS), H2-temperature-programmed reduction analyses (H2-TPR) and transmission electron microscopy (TEM). The results showed that the cobalt modified samples retained the highly ordered mesopore structure of MCM-41. In addition, the cobalt species on Co-MCM-41 was highly dispersed in the silica framework of MCM-41 molecular sieves, while the cobalt on Co-MCM-41_imp was present as cobalt oxide clusters or Co3O4 nano-particles on the external surface of MCM-41. The non-thermal plasma catalytic performance of the catalysts was evaluated by toluene oxidation using a dielectric barrier discharge (DBD) reactor. The results showed that the Co-MCM-41 exhibited better catalytic activity and stability than Co-MCM-41_imp. The main reason for the enhanced catalytic performance and stability was attributed to the well dispersion of cobalt species, good ozone decomposition activities and the high ability to degrade organic intermediates on catalyst surface.