Synthesis and catalytic properties of praseodymium oxide (Pr6O11) nanorods for diesel soot oxidation

In this study, a series of praseodymium oxides (Pr6O11) was developed by CTAB-assisted coprecipitation method. The praseodymium oxides were deeply characterized by XRD, N2 adsorption, SEM, HR-TEM, H2-TPR, soot-TPR, NO-TPO and in situ DRIFTS, and tested for soot combustion in absence/presence of NO atmospheres under tight/loose contact conditions. As a non-noble metal and single element oxide, the Pr6O11 catalysts exhibited excellent catalytic performances for both soot oxidation (T10 = 341 ℃, T50 = 395 ℃) in O2 and NOx adsorption (NAC, 906 μmol/g) at low temperature. It was believed that the relatively large surface area, strong NO oxidation ability and high intrinsic activity contributed to the superior performances. A promoting effect on soot oxidation was found when NO introduced, which was ascribed to the NOx-assisted mechanism. The in situ DRIFTS was used to explore the possible mechanism in the soot oxidation reaction process. The carboxyl was detected over Pr6O11 and was speculated as carbon-oxygen intermediate in soot oxidation. •Praseodymium oxides (Pr6O11) nanorods were synthesized by a CTAB-assisted coprecipitation method.•The as-prepared Pr6O11 nanocatalysts exhibited excellent soot removal ability and NOx adsorption capacity.•Large surface area, high reactivity of oxygen species and strong NO oxidation ability contributed to the good performances.•The “nitrite route” pathway was speculated in NOx adsorption.•The intermediate species (carboxyl) were detected in soot oxidation process.