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 degrees C, T50 = 395 degrees C) in O2 and NOx adsorption (NAC, 906 mu mol/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.