V2O5/hematite catalyst for low temperature selective catalytic reduction of NOx with NH3

Abstract

A series of V2O5/hematite (V/H) catalysts were prepared by impregnation of goethite with NH4VO3 solution and used in the selective catalytic reduction (SCR) of NO with NH3. The catalysts were characterized by X-ray diffraction, transmission electron microscopy, N2 adsorption, H2 temperature-programmed reduction, and NH3 temperature-programmed desorption. The effects of V2O5 loading and calcination temperature on the SCR activity were investigated. The NO conversion over 3% V/H catalysts calcined at 300 °C exceeded 95% at 250–300 °C. Neither H2O nor SO2 (0.01%) had any adverse impact on the activity, but a decrease of SCR activity was observed after high concentrations (0.03% and 0.05%) of SO2 were introduced. Cutting off the SO2 supply resulted in activity restoration. The simultaneous addition of 5% H2O and 0.03% SO2 led to a synergistic poisoning effect, but when these gases were switched off, the activity was recovered. SO2 adsorption on the catalyst surface led to the decrease in SCR activity.