Study of catalytic oxidation of toluene using Cu-Mn, Co-Mn and Ni-Mn mixed oxides catalysts

The successful synthesis of AMn2O4 (A = Co, Cu and Ni) spinels via solution combustion synthesis was achieved in less time than other methods. All catalysts with the same nitrate fuel ratio were used in the oxidation of toluene and the relationship between their proprieties and activities was investigated. Among all, nickel manganite exhibited the most promising activity and by changing the fuel ratio, it was sought to obtain the most appropriate structure for the reaction studied. Physico-chemical analysis, were used to define the characteristics of the synthesized catalysts. The results showed the successful synthesis of spinels and indicated that other materials peaks (single oxide phases) exist in the catalyst structure. BET-BJH analyzes reveal the mesoporous structures and given the limitations of the equipment were all classified as less than 10 m2/g. The influence of the urea content used is evidenced by the observation of the images by SEM. The particle size increases as the fuel ratio is higher. Samples of NiMn1.67 and NiMn2.08 showed larger and denser, sparsely dispersed clusters. By simultaneously considering reactor analysis and test results, it was found that the synthesized catalyst with a fuel n ratio of 0.5 has the best performance on toluene oxidation.