Mechanistic insight into the mutual-effect and key intermediate during methanol accelerating toluene decomposition over Co-spinel catalyst revealed by PTR-TOF-MS and DFT calculation

Revealing the inherent mechanism of multi-component VOCs paves the way for the development of new efficient catalysts applicable to the practical elimination of VOCs. For two primary co-existing industry VOCs of toluene and methanol, their synergetic and efficient oxidation are investigated based on two Co3O4 catalysts with exposed {111} and {110} faces. The promoting effect of methanol on toluene oxidation, with a significant decrease in conversion temperature compared to that of toluene alone, has experimentally and theoretically identified for the first time. The formaldehyde produced by methanol oxidation reacts with toluene to form 2-methylbenzaldehyde as a key intermediate, leading to a lower energy barrier in the aromatic-ring-opening of toluene during the oxidation path. The intrinsically higher conversion temperature of toluene than methanol synchronously guarantees the full decomposition of methanol. This work sheds light on a new insight into the reaction mechanism of the mutual-effect produced by multi-component VOC oxidation.