Synthesis and characterization of Mn3O4 and Mn2O3 nanocrystals on SBA-15: Novel combustion catalysts at low reaction temperatures

A simple method established in the present study has proven to be effective on the synthesis of Mn3O4 and Mn2O3 nanocrystals by using mesoporous silicas (SBA-15) as nanoreactor. These catalysts were characterized by XRD, TEM, N2-physisorption and laser Raman spectroscopic techniques. The structures obtained by thermolysis of Mn(II and III) acetylacetonates on SBA-15 were confirmed by XRD and Raman analysis. TEM characterization in combination with N2 physisorption studies reveal that nanoparticles partially occupying the pores of SBA-15. The nanocrystals of Mn3O4 and Mn2O3 on SBA-15 exhibited tremendous catalytic activities during the steady-state CO oxidation at low reaction temperatures (below 523 K). The catalytic activity of these catalysts was found to be higher compared with traditional MnOx impregnated on SBA-15 catalysts. For the sake of comparison, the commercial Mn2O3 and Mn3O4 were also tested for the CO oxidation.