Preparation and characterization of manganese oxide catalysts supported on alumina and zirconia-pillared clays

The preparation of manganese oxide catalysts supported (10 wt% MnO2) on pillared clays is presented. A saponite and a montmorillonite intercalated with aluminium and zirconium oligomers and calcined at 500 degrees C, were used as supports in addition to the starting natural clays. The impregnation with manganese(II) nitrate produced a loss of 14-36% of the specific total surface area of the clays intercalated with aluminium and zirconium polycations. Similar tendencies were found for the specific micropore volumes although the micropore size distributions remained almost unchanged. After calcination at 500 degrees C, the presence of poorly dispersed beta-MnO2 and alpha-Mn2O3 has been detected by X-ray diffraction and confirmed by temperature-programmed reduction analyses. The results suggested that weak interaction is established between manganese oxides and the pillared clays. (C) 2000 Elsevier Science B.V. All rights reserved.