Samarium Doped Ceria-based Materials The Performance For Soot Particles Combustion Activity

Diesel engines have been widely used in the vehicle industry and machinery due to thestrong dynamic performance, durability and economy. The emission of soot particulates fromdiesel engines has led to serious atmospheric pollution. In recent years, the haze phenomenonis more and more serious. The PM is the main pollutant. PM2.5is considered to be the culpritcausing haze. However, diesel exhaust contains a lot of PM and soot particles are the maincomponent. Soot oxidation temperature is at600oC, but diesel exhaust gas temperatures liebetween200and400oC. A suitable catalyst is required to promote soot combustion and it isnecessary to apply oxidation catalysts to increase the oxidation rate of the soot particulates atlower temperature. This requires an efficient catalyst for simultaneous removal of NOxandsoot.This paper examines the samarium doped ceria-based materials the performance forsimultaneous removal of NOx.First, ceria-based oxide catalysts and perovskite oxide catalysts have been investigatedfor catalytic soot oxidation reaction. It was found that the catalytic activities of ceria-basedoxide catalysts can be improved by loading LaCoO3. The50wt%LaCoO3/CeO2catalystshows the excellent catalytic activity for soot oxidation. The main reason is that oxygenstorage capacity of ceria and the LaCoO3enhances the bulk oxygen mobility on the catalystsurface.Second, doping of ceria with other rare earth elements promotes thermal stability ofcatalyst. Different Ce-Sm oxide catalysts for soot oxidation are prepared through thecomplex-combustion method. The Ce-Sm forms solid solutions and promotes thermalstability of catalyst. The small amount of doping Sm catalyst shows the excellent catalyticactivity for soot oxidation is at lower tempertures.Last, active metal support of Ce0.75Sm0.25O2can significantly affect the catalyticproperties. Ag/Ce0.75Sm0.25O2catalyst shows the excellent catalytic activity for soot oxidationwith the O2. And Mn/Ce0.75Sm0.25O2catalyst shows the excellent catalytic activity for sootoxidation with the NOx.