Role of stable nitrates stored on BaCoCe in soot catalytic oxidation

BaCoCe catalysts were prepared by impregnating different amounts of barium acetate on Co–Ce mixed oxides. The optimal Ba loading amount is 10 mol.% of Ce, and the obtained catalyst presents a maximal soot oxidation rate temperature at 378 °C in NO + O2 under loose contact conditions. The NOx storage capacity of BaCoCe is twice of that of CoCe, and the decomposition of the stored nitrates is pronouncedly delayed. The soot is ignited at 358 °C by NO2 produced from decomposition of the relatively stable nitrates with heat transfer limitations.