Study on the Reaction Performance of Ce- and Co-Modified Mn-Based Catalysts in C3H6-SCR

The C3H6-SCR de-NOx technology has received widespread attention due to its significant development potential. Through Mny/γAl2O3 catalyst activity testing, the catalytic performance of the Mn5/γAl2O3 catalyst was the best, and the NO conversion could reach 60% at 275 °C. Afterward, Ce/Co modification was carried out on the Mn5/γAl2O3 catalyst to prepare catalysts with different Ce/Co loadings, and activity testing was conducted. It was found that the catalytic performance of the catalyst was significantly improved after doping with promoters, and the improvement of catalytic performance by Ce was much stronger than that of Co, and the doping of Ce also reduced the optimal reaction temperature. Through NO-TPD and H2-TPR, it can be found that, after doping with Ce, the catalyst's ability to adsorb NO and oxidation–reduction were stronger than those of Co-doped catalysts, which explained the higher catalytic performance of Mn5/Ce10-γAl2O3 catalyst. In a comparison of the characterization results of the Mn5/Ce10-γAl2O3 catalyst before and after the reaction, it can be found that the Mn5/Ce10-γAl2O3 catalyst had good reaction stability. The addition of Ce4+ can lead to the formation of the Mn–O–Ce bridge, thereby strengthening the binding between Mn and O and further promoting the progress of C3H6-SCR. Finally, through in situ DRIFTS, it was found that the reaction of C3H6-SCR on the Mn5/Ce10-γAl2O3 catalyst followed the oxidation–reduction mechanism and generated the important intermediate product −NH.