Investigation of Low-Temperature Selective Catalytic Reduction of NO_x with Ammonia over Mn-Modified Fe₂O₃/AC Catalysts

A series of iron-based catalysts supported on activated carbon (AC) and manganese-modified Fe₂O₃/AC catalysts with various Fe:Mn ratios were prepared for selective catalytic reduction (SCR) of NO by ammonia at low temperature. It was found that the addition of a small amount of MnO_x into the Fe₂O₃/AC catalyst contributed to an improvement of the NO conversion. NO conversions of approximately 100% were obtained for the 10FexMn/AC (x = 1, 3, 5) catalysts at 180-240 ºC. The characterization results indicate that the addition of a certain amount of MnO_x into the 10Fe/AC catalyst increased the dispersion of the amorphous state, increased the ratios of Fe³⁺/(Fe³⁺ + Fe²⁺) and Mn⁴⁺/Mn³⁺, and improved the surface area and pore volume.

Keywords:
Fe₂O₃/AC; manganese oxide; NH₃-SCR; NO conversion