The effect of cerium–praseodymium catalyst on soot oxidation in diesel engine exhaust

Pr-doped CeO 2 catalysts are investigated for low-temperature soot oxidation under controlled thermogravimetric conditions. A series of Ce 1−y Pr y O x mixed oxides ( y  = 0.1–0.5) are synthesized using a hydrothermal precipitation method. The effects of Pr incorporation and soot-to-catalyst mass ratio on soot oxidation are evaluated by thermogravimetric analysis. The results show that Pr incorporation improves soot oxidation activity compared with pure CeO 2 . Among the investigated catalysts, Ce 0.9 Pr 0.1 O x with a nominal Pr/(Pr+Ce) ratio of 0.1 exhibits the highest catalytic activity, with the lowest peak combustion temperature and the highest maximum reaction rate. Further optimization of the soot-to-catalyst mass ratio shows that a ratio of 1:3 provides the best oxidation performance, with a peak combustion temperature of 432.7 °C and a maximum reaction rate of 41.6%min −1 . XRD results reveal changes in lattice parameters and crystallite size after Pr incorporation into CeO 2 , while SEM analysis shows variations in particle morphology and aggregation behavior. XPS analysis indicates changes in the relative proportion of surface Ce 3+ species among different catalysts. These results suggest that Pr incorporation modifies the structural and surface properties of CeO 2 , which may contribute to enhanced soot oxidation activity under laboratory-scale TGA conditions.