Catalytic oxidation of soot by CeO2–ZrO2 catalysts: Role of Zr

Human health has been adversely affected by the soot particles in the exhaust of diesel engines. In this study, ceria-zirconia supported 1, 3, and 5 wt% zirconium (Zr) catalysts were prepared using the co-precipitation method and tested for soot combustion. The chemical and physical properties of catalysts were evaluated through NH3-temperature-programmed desorption (NH3-TPD), scanning electron microscopy (SEM), physisorption analysis, Raman spectroscopy, H2-temperature programmed reduction (H2-TPR), and X-ray diffraction (XRD). The catalytic activity of the catalysts for soot combustion was tested in loose contact through thermo-gravimetric analysis (TGA). Nitrogen and air atmosphere were used for the combustion of model soot. 3 and 5 wt% Zr/CeO2–ZrO2 showed higher soot oxidation than 1 wt% Zr/CeO2–ZrO2 in the nitrogen atmosphere, whereas percentage weight loss of model soot was high with 1 wt% Zr/CeO2–ZrO2 than 3 and 5 wt% Zr/CeO2–ZrO2.