Improvement of sulfur and water resistance with Fe-modified S-MnCoCe/Ti/Si catalyst for low-temperature selective catalytic reduction of NO with NH.

The low-temperature SCR of NO by NH is restricted in application since the catalysts is easily poisoned by sulfur and water. The Fe modified Mn-Co-Ce/TiO/SiO catalysts synthesized via impregnation method and sulfating were evaluated for low-temperature NH-SCR in the presence of SO and HO. The calcination temperature and loading amounts of Mn, Fe, Co and Ce were optimized. Adding of Fe into S-MnCoCe/Ti/Si played an important role in resistance to sulfur and water poisoning. The optimal calcination temperature was 380 °C and the optical mass loading of the catalyst was 10% of Mn, 10% of Fe, 1% of Co and 4% of Ce. The optimal S-MnFeCoCe/Ti/Si catalyst maintained high NO conversion of 93% at reaction temperature of 160 °C in the presence of 50 ppm SO and 10 vol% HO. The catalytic activity did not continue to fall after two times of repeated used in the temperature range of 100-200 °C, indicating its excellent sulfur and water durability and stability in the presence of SO and HO. The interaction between MnO and FeO enhanced sulfur and water durability rather than other bi-metal interactions. Furthermore, the mechanism of Fe improving resistance to SO and HO was discussed.