SOOT OXIDATION ON SUPPORTED CATALYSTS - EFFECTS OF PRETREATMENT AT HIGH-TEMPERATURES

It was shown by TPR measurements that cobalt, a promising candidate for catalyst coatings on self-regenerating diesel soot filters, forms aluminate phases with various ceramic supports, when heated to 800- 1000°C. Thus, under real conditions, such aluminate phases, and not supported oxides would make up the actual catalyst. Surprisingly enough no differences in the catalytic activity for soot burning could be detected between cobalt oxides and cobalt aluminates. Since cobalt aluminates are difficult to reduce below some 800°C, the present results seem to be inconsistent with the commonly accepted redox mechanism of the catalysis of carbon oxidation. © 1990.