Catalytic Combustion of Soot over the Highly Active (La_(0.9)K_(0.1)CoO3)_xmCeO2 Catalysts

摘要

The highly active (La_(0.9)K_(0.1)Co_3)_xmCeO2 catalysts consisting of comparably sized La_(0.9)K_(0.1)CoO3 active component and CeO2 support nanoparticle were studied on the catalytic combustion of soot by temperature-programmed oxidation (TPO) technique. The properties of oxygen species and the redox performances of catalysts were investigated by the method of O2-TPD and H2-TPR. During TPO process, all supported oxide catalysts showed lower T_m than the corresponding.nanometer CeO2 support or pure La_(0.9)K_(0.1)CoO3 perovskite. The best catalytic activity was obtained over (La_(0.9)K_(0.1)CoO3)_(20)mCeO2 catalyst (T_m= 354°C), and its catalytic activity for the combustion of soot is as good as supported Pt catalysts. During the catalytic combustion of soot, the surface a oxygen species should play an important role. The formation of surface oxygen-containing complexes (SOC) may be one of the key intermediate species according to the results of in situ DRIFT, and NO2 released by surface nitrate species remarkably promote the soot oxidation.