Effect of SO2 on a cordierite honeycomb supported CuO catalyst for NO reduction by NH3

Abstract

Supporting CuO on a Al 2 O 3 -coated cordierite honeycomb yields a good catalyst (CuO/HC-Al) for selective catalytic reduction (SCR) of NO with NH 3 at 350-500°C. SO 2 has complex effects on the catalyst's activity. It significantly promotes the SCR activity through conversion of CuO to CuSO 4 , however, when a certain amount of CuO is converted, it slightly decreases the SCR activity through competitive adsorption with NH 3 . This competitive adsorption reduces the amount of NH 3 adsorbed on the catalyst surface, especially on the sites highly active to the SCR. It also prevents transformation of CuO to CuSO 4 and as a result, the catalysts subjected to pre-sulfation and in situ sulfation show different SCR behaviors.