CeO2 Modified Mn-Fe-O Composites and Their Catalytic Performance for NH3-SCR of NO

The ammonia selective catalytic reduction (NH3-SCR) technology is still necessary to further develop denitration catalytic materials which have good catalytic activity, high stability and environmental friendliness at relatively low temperature (<300 degrees C). In this work, the Mn-Fe-O catalyst was prepared by oxalate co-precipitation method and modified with different contents of CeO2 for low temperature NH3-SCR of NO. The catalysts were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption, X-ray photoelectron spectroscopy (XPS), temperature programmed reduction or desorption (H-2-TPR, NH3-TPD). The catalytic results show that as compared with pure Mn-Fe-O sample, Mn-Fe-O modified with suitable CeO(2 )content shows much better performance for NH3-SCR with 95% conversion of NO and a high N-2 selectivity at 80 degrees C under the same reaction conditions. CeO2 modification increases the content of Fe3+, Mn3+ and Mn4+, and the number of surface acid sites on the surface of Mn-Fe-O oxide, which contribute to the adsorption of NH3 and the catalytic reaction. In addition, redox reactions among Fe2+/Fe3+, Mn2+/Mn3+/Mn4+ and Ce3+/Ce4+ pairs improve the redox ability and stability of the catalyst.