Comparative study on transition element doped Mn-Zr-Ti-oxides catalysts for the low-temperature selective catalytic reduction of NO with NH3

摘要

The effect of Cu, Fe, Co, Ni, Cr and Zn on Mn-Zr-Ti mixed oxides catalysts introduced by co-precipitation was investigated. The Mn-Co catalyst showed the highest NO conversion near 100% and a good N-2 selectivity >90% at 200-300 degrees C. Comparing with the Mn-non catalyst, the Mn-Co catalyst presented a higher reaction rate constant at 120 degrees C with 23.3mls(-1)g(-1). The Mn-Co catalyst possesses a high concentration of Mn4+ and surface labile oxygen, which should improve the redox property and increase catalytic activity. Additionally, the Mn-Co showed the highest ratio of Lewis acid sites. The resistance to SO2 was improved by incorporation of Co. In summary, the Mn-Zr-Ti mixed oxides catalyst have a better N-2 selectivity than other Mn-based catalysts and could be improved by doping with Co.