Soot Combustion Catalysis by CeMn

The catalytic activity of cerium manganese catalyst for soot combustion was measured by means of TGA/DSC thermogravimetric analyzer (METTLER, Swiss) with Printex-U (Degussa, Germany) used as the model of diesel soot. The soot and the catalyst (weight ratio was 1:10) were carefully ground in a mortar for 10 min to achieve the “tight contact” condition. In order to make the evaluation condition similar to the actual condition, the catalyst and soot were mixed with shovel for 5 min to achieve the “loose contact” condition. The reaction test was carried out with 10% O₂/N₂ which was close to the oxygen concentration in diesel exhaust. Activity tests were carried out from 30 to 600 °C under a gas flow rate of 30 ml/min, and the heating rate was maintained at 10 °C/min. T_m represents the temperature corresponding to the maximum heat release during soot combustion in the DSC diagram and the peak value of the DTG curve (They're the same). The lower the T_m, the easier the combustion of soot and the better the activity of the catalyst. TPO-MS was used to detect the CO₂, CO and H₂O produced during the heating process (Supporting information).