New mixed perovskites LaFe xMn yMo zO3 were prepared, characterized and investigated as catalysts for the total oxidation of the model aromatic VOC (Volatile Organic Compound), toluene. The perovskites were characterized by XRD (X-Ray Diffractometry), Mössbauer spectroscopy, TPR (Temperature Programmed Reduction) and BET surface area determination. The results suggested the formation of the perovskite phase with incorporation of all metals in the structure. The catalytic studies were carried out in a Temperature Programmed Reaction system with toluene (1000 ppm) and synthetic air in the gas phase. It was observed that the oxidation of toluene starts at temperature as low as 280 ºC and that Mn is responsible for most of the catalytic activity. However, the presence of small amounts of Fe (LaFe0.27Mn0.73O3) leads to an increase in this activity. Stability studies showed that these perovskite catalysts are stable even after 100 h reaction at 400 ºC with no significant structural change, as observed by XRD and Mössbauer analyses.
lanthanum iron perovskite; toluene oxidation; catalytic oxidation; manganese; molybdenum
