Preparation, characterization and catalytic activity studies of CeO2–K diesel soot oxidation catalysts loaded on porous Al2O3 substrate using water-immiscible solvent

CeO2–K catalysts supported on porous alumina substrate have been prepared by using a novel water-immiscible solvent. The advantage of this method is to load the catalyst onto the filter surface by one-time coating and prevent depositing the catalyst into the porous structure of support materials. The catalytic activities of the supported catalysts were evaluated by TPR system and the results showed that the pure CeO2 displayed a poor catalytic activity for soot oxidation, while the addition of K element into CeO2 would result in the formation of CeO2–K solid solution and significant enhancement of catalytic activity. Nevertheless, the variation of K content had a limited effect on soot ignition temperature. The catalyst with a Ce:K molar ratio of 1:2 exhibited an ignition temperature of about 330 °C and the oxidation rates of about 0.16 and 0.28 mg min−1 cm−2 at temperatures of 370 and 390 °C, respectively.