Catalytic N2O decomposition on Pr0.8Ba0.2MnO3 type perovskite catalyst for industrial emission control

Ba substituted PrMnO3 type perovskite catalysts (Pr1-xBaxMnO3 with x = 0.1-0.4) have been studied for N2O decomposition reaction. These catalysts were prepared by a combination of co-precipitation and impregnation methods. They are characterized in detail by means of XRD, BET-SA, SEM, EDX, O-2-TPD, H-2-TPR and XPS analysis. The catalytic activity of Ba substituted PrMnO3 catalyst was observed to be relatively better than the bare catalyst, thereby showing the promotional effect of barium, and Pr0.8Ba0.2MnO3 with 20 mol% substitution was found to be the optimized composition. The Pr0.8Ba0.2MnO3 catalyst composition was also prepared in supported form using ceramic honeycomb by following in situ co-precipitation method and tested for N2O decomposition reaction under simulated feed conditions. Supported catalyst shows 92% conversion of N2O at 550 degrees C with a maximum of 0.0984 mmol of N2O decomposed per gram of the catalyst, per unit time in the presence of NO and O-2, which was higher than that obtained for unsupported catalyst. O-2-TPD studies inferred that Ba incorporation results in increase of Mn4+/Mn3+ ratio of PrMnO3 catalyst, thereby confirming the substitution of Ba in perovskite structure. TPR studies also provided the clear evidence to this effect. This improved redox property of Ba substituted perovskite catalyst was correlated to its enhanced catalytic activity for N2O decomposition. (C) 2012 Elsevier B. V. All rights reserved.