Different valent ions-doped cerium oxides and their catalytic performances for soot oxidation

Abstract

The nmCeO 2 and Ce 0.8M 0.2O 2 (M = Sm, Zr, V) nanoparticles were prepared by the method of microwave-assisted heating decomposition. Their catalytic performances for diesel soot oxidation were investigated with temperature-programmed oxidation reaction (TPO). Spectroscopic techniques (XRD, Raman, UV-Vis DRS and FT-IR) were utilized to characterize the structures of nmCeO 2 and Ce 0.8M 0.2O 2 catalysts. The results show that the structures of the catalysts depend on the different doped ions. Ce 0.8Sm 0.2O 2 and Ce 0.8Zr 0.2O 2 still preserved a face-centered cubic fluorite structure of CeO 2. However, CeVO 4 crystallite was formed as V doping (Ce 0.8V 0.2O 2). Nanometer CeO 2, Ce 0.8Sm 0.2O 2 and Ce 0.8Zr 0.2O 2 exhibited higher catalytic activity than conventional CeO 2 and Ce 0.8V 0.2O 2 for soot combustion due to the nanometer effect and the good contact between the catalyst and soot. For soot oxidation, nmCeO 2 is mainly active components. However, the doping of Sm or Zr could remarkably improve the thermal stability of nmCeO 2, and the doping of Sm or V could enhance the ability to resist SO 2 poison of catalysts.