Two easy methods to increase SO2-resistance ability of Mn-based catalyst

Manganese-based catalysts show high activities in selective catalytic reduction of nitrogen oxide (NO), but easily deactivated by sulfur dioxide. In this work, operation sequence and rare-earth-element doping were investigated to increase the anti-SO2 ability of Fe-doped manganese oxide (FM300). On one hand, when the catalyst pre-adsorbed NH3, SO2 only decreased the NO conversion from 100 % to 75 % at 200 °C. Otherwise, the conversion was decreased to 30 %. In-situ Diffuse Reflection Fourier Transform Infrared Spectroscopy proved that NH3 competed with SO2 and protected part of the Brønsted acidic sites. On the other hand, rare-earth-element doping increased the long-time anti-SO2 performance of FM300 from 150 min to 300 min (Sm-FM300) and > 700 min (Ho-FM300). Differential Scanning Calorimeter analysis indicated that Ho optimized ferromagnetism of FM300, which was in favor of NH3 adsorption. The main result of this work will help to increase applicability of the manganese-based catalyst.