Formaldehyde/methanol combustion on alumina-supported manganese-palladium oxide catalyst

Alumina-supported manganese catalysts with manganese loadings ranging from 3.9 to 18.2 wt.% were prepared and tested in the combustion of formaldehyde/methanol mixture in an air stream. All the catalysts achieved total combustion in the temperature range 150-230degreesC and activity increased with increasing manganese loading. The 18.2% Mn/Al2O3 catalyst produced total combustion at 220 degreesC, but this temperature is decreased to 90 degreesC when 0.1% Pd is incorporated to this catalyst. The catalysts were characterised by X-ray diffraction (XRD), temperature programmed reduction (TPR) and X-ray photoelectron spectroscopy (XPS). These techniques pointed out that MnO2 and Mn2O3 phases are present on the surface of calcined catalyst. The oxidation ability of these phases appears to be responsible for catalyst activity. Activity is enhanced when small amounts of Pd are incorporated to the catalyst with the highest Mn-loading (18.2% Mn/Al2O3). (C) 2004 Elsevier B.V. All rights reserved.