Promotional Effect of Doping Aluminum on the Sulfated Fe2o3 Catalyst in Nh3-Scr Reaction

FemAlnOx catalysts were synthesized by the co-precipitation method and sulfated by (NH4)2SO4 impregnation method. Among the catalysts, 1.2S/Fe3Al1Ox exhibits more than 90% NO conversion in the range of 260−410 ℃ both in the catalytic activity and the resistance to K poisoning testing. Structures and physicochemical properties of catalysts were measured via different characterization techniques. Through comparative studies between 1.2S/Fe2O3 and 1.2S/Fe3Al1Ox, it is found that doping Al into Fe2O3 can reduce its particle size, increase its specific surface area, and suppress the formation of crystalline phase Fe2(SO4)3 at high calcination temperature, which is propitious to generate more surface sulfates on FemAlnOx. NH3-TPD and in-situ DRIFTS prove that K ions preferentially interact with surface sulfates, and more surface sulfates can provide more Brönsted acid sites to obtain higher ability of resistance to K poisoning. This work provides a simple strategy to improve the catalytic performances of Fe-based catalysts.