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

The nmCeO2 and Ce0.8M0.2O2 (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 nmCeO2 and Ce0.8M0.2O2 catalysts. The results show that the structures of the catalysts depend on the different doped ions. Ce0.8Sm0.2O2 and Ce0.8Zr0.2O2 still preserved a face-centered cubic fluorite structure of CeO2. However, CeVO4 crystallite was formed as V doping (Ce0.8V0.2O2). Nanometer CeO2, Ce0.8Sm0.2O2 and Ce0.8Zr0.2O2 exhibited higher catalytic activity than conventional CeO2 and Ce0.8V0.2O2 for soot combustion due to the nanometer effect and the good contact between the catalyst and soot. For soot oxidation, nmCeO2 is mainly active components. However, the doping of Sm or Zr could remarkably improve the thermal stability of nmCeO2, and the doping of Sm or V could enhance the ability to resist SO2 poison of catalysts.

The catalytic combustion of soot over Ce-based nanoparticles was a gas–solid–solid three-phase complex reaction. Different doping ions and reaction gas remarkably affect the catalytic performances of materials.Figure optionsDownload high-quality image (177 K)Download as PowerPoint slideHighlights
► Ce-based nanoparticles were synthesized by means of microwave-assisted heating decomposition.
► The influence of NOx and SO2 on catalytic performances was investigated by the in situ DRIFT method.
► The redox and catalytic property of CeO2 is strongly influenced by doping different valent ions.