Three-dimensional ordered macroporous cerium-manganese composite oxide for NO oxidation

NOx is one of the main sources of air pollution, which primarily comes from automobile exhausts. Rare earth-based catalysts for NO oxidation have excellent oxygen storage and release performance and good structural stability. Herein, a series of three-dimensional ordered microporous (3DOM) cerium-manganese composite oxide catalysts with different cerium-manganese ratios for NO oxidation were prepared by the sol-gel method. The 3DOM structure improves the contact efficiency of the NO, soot and the catalyst. By incorporating Mn3+ ions into the cerium oxide lattice, a Ce-Mn solid solution forms with an ordered macroporous structure, and the interaction between cerium and manganese significantly increases the amount of reactive oxygen species. The catalyst with the optimal cerium-manganese ratio (1 : 2) was able to achieve a conversion rate of 62% at 250 degrees C, and the highest conversion rate reached 98%, which is far higher than pure cerium oxide and pure manganese oxide catalysts. This work provides a promising catalyst for NO oxidation and soot combustion applications. Three-dimensional ordered microporous cerium-manganese composite oxide catalysts with different cerium-manganese ratios were prepared by a sol-gel method for NO oxidation and soot combustion.