A Green CeO₂−WO₃/TiO₂ Medium‐Low Temperature de‐NO_x Catalyst for Selective Catalytic Reduction of NO_x with NH₃

Abstract

A series of CeO 2 À WO 3 /TiO 2 catalysts were synthesized by the co-precipitation method and used for selective catalytic reduction (SCR) of NO with NH 3 under medium-low temperature conditions with metatitanic acid as Ti source. A more reasonable weight ratio of CeO 2 and WO 3 was explored. The catalytic activity enhanced with the increase of cerium content, but the catalytic activity changed slightly in the temperature range of 240°C to 400°C when the cerium content exceeded 15 %. Tungsten could enhance the sulfur resistance by adjust-ing the degree of crystallization, acidity in the SCR process. When the weight ratio of CeO 2 to WO 3 was 15: 8, the conversion rate of NO was more than 90 % in the temperature range of 240°C to 440°C. For 15 %CeO 2 -8 %WO 3 /TiO 2 catalyst, the NO conversion was maintained around 84 % when the mixed gas was introduced SO 2 . At the same time, we have optimized the selection of carriers, metatitanic acid as a carrier was better than titanium dioxide.