Characterization and activity of cobalt oxide catalysts for total oxidation of hydrocarbons

In view of the importance of catalytic combustion in the field of air pollution control, a study on the total oxidation of lean mixtures of hexane (approximately 0.5 mol%) in air was undertaken. Silica-supported cobalt oxide catalysts prepared by the impregnation of silica hydrogel by ammoniacal cobalt oxalate precursor effectively catalysed the total oxidation at 553 K. The dependence of the catalyst activity on the temperature and environment during decomposition was investigated. A low decomposition temperature and an inert environment yielded better activity of the catalysts. This has been explained with the help of the decomposition mechanism of cobalt oxalate and has been supported by estimating the particle size distribution by X-ray diffraction analysis.