Effect of preparation methods on the activity of VOx/CeO2 catalysts for the selective catalytic reduction of NOx with NH3

Abstract

The effect of preparation methods on the activity of VO_x/CeO₂ catalysts for the selective catalytic reduction of NO_x with NH₃ was fully studied. VO_x/CeO₂ prepared by a simple homogeneous precipitation method showed higher NH₃-SCR activity and higher SO₂ and H₂O resistance than catalysts prepared by other methods. Lower CeO₂ crystallinity on the surface, better dispersion of vanadium species, and higher surface concentration of vanadium species together with more acid sites were all responsible for the higher SCR activity of VO_x/CeO₂ prepared by the homogeneous precipitation method. The NH₃-SCR reaction over VO_x/CeO₂ catalysts mainly followed the Eley–Rideal mechanism, in which gaseous NO reacted with adsorbed NH₃ species to finally form N₂ and H₂O.