Toluene and 2-propanol mixture oxidation over Mn2O3 catalysts: Study of inhibition/promotion effects by in-situ DRIFTS

[Display omitted] •Mn2O3 oxides are active for the oxidation of toluene, 2-propanol and their mixture.•Mn2O3 catalyst prepared by Citrate-Gel method has the best catalytic performances.•The presence of both VOCs promoted the deep oxidation of each other on Mn2O3.•The promotion effect of binary mixture above 200 °C was proven by in-situ DRIFTS.•DRIFTS allowed to identify the reaction intermediates in different scenarios. Three Mn2O3 catalysts were synthetized by different methods, characterized and tested in toluene and 2-propanol (iPrOH) oxidation in single and binary component mixture. In single VOC media, the catalytic activity was strongly influenced by the specific surface area, low-temperature reducibility and active surface-oxygen species. In the binary VOCs mixture oxidation, light-off curves were shifted to lower temperatures, suggesting a promoting effect on the catalytic activity for toluene and iPrOH oxidation. The acetone production in binary mixture was also shifted to lower temperatures. The obtained results were rationalized based on the different polarity of the VOCs, the available adsorbed oxygen and the exothermic character of the VOCs combustion. These promoting effects were pointed out by in-situ DRIFTS measurements, in which the pre-adsorption of any of these two VOCs affected the adsorption/reaction of the other. For the first time, in-situ DRIFTS has been applied to elucidate the reaction mechanisms of the oxidation of toluene/2-propanol mixture on Mn2O3, which allowed to correlate the surface phenomena and the catalytic performance.