Investigation of Low-Temperature Selective Catalytic Reduction of NOx 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 MnOx 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 degrees C. The characterization results indicate that the addition of a certain amount of MnOx 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.