Effect of Ce and Mn on 3DOM La_0.8Sr_0.2MnO₃ perovskite in soot combustion under different atmospheres

Fabrication of high-performance soot combustion catalyst and clarification the reaction mechanism has been of great importance but rarely achieved. Herein, a series of three-dimensionally ordered macroporous La_0.8Sr_0.2MnO₃ perovskite were fabricated and further decorated by Ce and Mn. The well-dispersed CeO₂ on the surface of perovskite could accelerate the adsorption and activation of gaseous oxygen, therefore promoting the oxidation process. The further introduction of Mn was conclusive to the storage and utilization NOx, which was beneficial for soot combustion with the assistance of NOx. According to the catalytic performance tests and DRIFTS, CeO₂-loaded catalysts tended to follow the active oxygen species derived reaction, with lowest T₅₀ of 460 °C for C₁/LSM under 5 % O₂/N₂ atmosphere. While CeMnO_x-loaded catalysts were inclined to follow the NOx-assisted catalytic reaction, and the generated nitrate species would directly participate in the reaction. The T₅₀ of C₁M₂/LSM further decreased to 397 °C under 0.05 % NO + 5 % O₂/N₂ atmosphere. This work was not only devoted to design high performance catalysts for soot oxidation, but also to reveal the catalytic mechanism of these catalysts under different atmospheres.