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, O2-TPD, H2-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 °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 O2, which was higher than that obtained for unsupported catalyst. O2-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.

Catalytic activity of PrMnO3 for N2O decomposition reaction is increased by Ba promotion and it appears that Ba incorporation alters the properties of perovskite structure, such as valence state of Mn and oxygen desorption. This was confirmed by TPD as well as TPR analysis.Figure optionsDownload high-quality image (109 K)Download as PowerPoint slideHighlights
► Catalytic N2O decomposition activity of PrMnO3 is increased by Ba substitution.
► Ba incorporation alters the redox properties of perovskite.
► The altered redox properties of Pr0.8Ba0.2MnO3 are studied by TPD as well as TPR analysis.
► Supported Pr0.8Ba0.2MnO3 shows 92% conversion in the presence of O2 and NO at 550 °C.