Comparative study of La1-xCexMnO3+δ perovskites and Mn-Ce mixed oxides for NO catalytic oxidation

A series of La1-xCexMnO3+delta (x = 0, 0.05, 0.1, 0.2, and 0.3) perovskites and Mn-Ce mixed oxides were prepared. Their physico-chemical properties were systematically characterized and the NO oxidation activities of the catalysts were investigated. The La1-xCexMnO3+delta has the best activity among all of the catalysts, with a maximum NO conversion of 85% at 300 degrees C. The characterization results indicate that the doping of Ce improves the properties of the perovskites in terms of the specific surface area, the average valence state of Mn ions, the number of reactive oxygen species and the NOx desorption behaviors. The Mn-Ce mixed oxide calcined at 500 degrees C shows a similar NO oxidation activity with La0.9Ce0.1MnO3+delta. However, the activity of the mixed oxide obtained at 750 degrees C decreases a lot, which results from the loss of active sites and active oxygen species. (C) 2020 Published by Elsevier B.V. on behalf of Chinese Society of Rare Earths.