Mn and Fe oxides co-effect on nanopolyhedron CeO2 catalyst for NH3-SCR of NO

The active components Mn and Fe oxides were loaded on the surface of CeO2 catalyst with nanopolyhedrons morphology (CeO2-NPs) by impregnation method to improve the CeO2-NPs catalyst catalytic performance. The activity test results showed that the activity order of these catalysts within the temperature of 100-300 degrees C was Fe-Mn-Ce > Mn-Ce > Ce catalyst, and the NO conversion rate of Fe-Mn-Ce catalyst was the highest at 200 degrees C, which was about 98%. The performances of these catalysts were further investigated by SEM, XRD, XPS, Raman spectra, H-2-TPR, NH3-TPD and in situ DRIFT. The results indicated that Fe-Mn-Ce catalyst possessed the best reducibility and surface acidity of the three catalysts. According to the XPS and Raman spectra tests, the sequences of the ratio of O-alpha/(O-alpha+O-beta) and Ce3+/(Ce3+ + Ce4+) were both Fe-Mn-Ce > Mn-Ce > Ce catalyst, which indicated that the Fe-Mn-Ce catalyst possessed the most oxygen vacancy and further improved the catalytic activity of the catalyst. Moreover, the Fe-Mn-Ce catalyst also exhibited the best tolerance to SO2 of the three catalysts at 225 degrees C. In general, simultaneous loading of manganese and iron oxides on the CeO2-NPs catalyst could effectively improve the low temperature SCR performance of the catalyst.

Automated summary

The research shows that loading manganese and iron oxide active components on the surface of CeO2 nanopolyhedrons catalyst can significantly improve its low temperature SCR performance. The Fe-Mn-Ce catalyst exhibits the highest NO conversion rate and best reducibility and surface acidity among the catalysts tested.