Effect of V2O5 Additive on the SO2 Resistance of a Fe2O3/AC Catalyst for NH3-SCR of NOx at Low Temperatures

The effect of vanadium oxide on an iron-based catalyst supported on activated carbon (AC) in the selective catalytic reduction of NO x by NH 3 (NH 3 -SCR) was investigated in this work. A series of vanadium-modified Fe 2 O 3 /AC catalysts were prepared by a coimpregnation method. The addition of a small amount of vanadium oxide contributed to the higher dispersion of iron species on the surface of the catalyst. Among various vanadium-modified iron catalysts supported on AC, 3% Fe–0.5% V achieved the best SCR activity and SO 2 tolerance. In the presence of H 2 O, SO 2 had a severe deactivation effect on both vanadium- and non-vanadium-modified catalysts, yet the inhibition effect of H 2 O and SO 2 was reversible on 3% Fe–0.5% V at relatively low space velocity. It was found that the vanadium additive promoted the formation of sulfate species. The formed sulfate species increased the surface acidity and thus enhanced the tolerance toward SO 2 .