KNO3 supported on three-dimensionally ordered macroporous La0.8Ce0.2Mn1-xFexO3 for soot removal

Three-dimensionally ordered macroporous (3DOM) La0.8Ce0.2Mn1-xFexO3 perovskites were successfully prepared by a colloidal crystal template method and KNO3-supported 3DOM La0.8Ce0.2Mn1-xFexO3 catalysts were prepared by a wetness impregnation method. Physicochemical properties of these catalysts were characterized by XRD, FT-IR, FESEM, TEM, BET, H-2-TPR, O-2-TPD, and XPS techniques and their catalytic performances were evaluated by soot combustion. All these perovskites possessed a well-ordered 3DOM structure, and KNO3 was highly dispersed on the skeleton of the supporters without changing the morphology and crystal structure of the perovskites. The 3DOM structure provides an increased contact area between the catalyst and soot. Besides, partial replacement of Mn by Fe into the perovskites increased the surface area and reducibility. The introduction of K ions increased the amount of active oxygen species in the catalysts, which could accelerate soot combustion at low temperature. On the other hand, the NO3- species brought by KNO3 were beneficial to the reaction at high temperature. Among all the samples, the 3DOM K/La0.8Ce0.2Mn0.6Fe0.4O3 exhibited the highest catalytic performance with the lowest T-50 at 379 degrees C.