In situ DRIFT spectroscopy study into the reaction mechanism of toluene over CeMo catalysts

The CeMo catalysts were prepared via different method and employed for the catalytic combustion of toluene. The influence of different preparation methods on CeMo samples for toluene oxidation was revealed. The toluene catalytic oxidation efficiency followed an order of CeMo-HT > CeMo-CP > CeMo-Sg. The long-term test indicated that the CeMo-HT possessed outstanding thermal stability. The excellent catalytic activity of CeMo-HT could be reasonably attributed to the smallest grain size, the highest number of low valence Ce3+ ions and Osur species. CeMo-HT catalyst prepared by the hydrothermal method possessed the richer oxygen vacancies, which promoted the deep oxidation of toluene, and effectively reduced the production of intermediates. However, CeMo-HT (aged) possessed poorer oxygen vacancies, and generated more by-products. Additionally, the two reaction pathways of the toluene were inferred. In pathway I for CeMo-HT (aged): toluene -> benzyl alcohol -> benzal-dehyde -> benzoic acid -> carbonate -> CO2 and H2O. In pathway II for CeMo-HT: toluene -> phenol -> benzo-quinone -> maleic anhydride -> CO2 and H2O.

Automated summary

This study investigated the influence of different preparation methods on CeMo samples for the catalytic combustion of toluene. The CeMo-HT catalyst prepared by the hydrothermal method showed the highest catalytic activity and thermal stability, attributed to the richer oxygen vacancies which promoted the deep oxidation of toluene.