Preparation and performance of V2O5-CeO2-SiO2 catalyst for the selective catalytic reduction (SCR) of NOx with NH3 at low temperature

摘要

Nitrogen oxides (NOx) from flue gas of industry can be removed efficiently by catalytic technology. However, materials development for selective catalytic reduction of NOx with ammonia (NH3-SCR) is still a challenging task especially at temperature below 200oC. A series of vanadium-ceria oxide supported on mesoporous silica catalyst were prepared by sol gel route with different Vanadia (V2O5) contents ranging from 0.2 to 5 w%. These catalysts were studied to see the effect of adding vanadia on the selective catalytic reduction (SCR) of NO2 with ammonia from ammonium bicarbonate, (NH4)HCO3. (NH4)HCO3 was pre-mixed with the catalyst and packed in a reactor operating at 120°C. Effect of V2O5 on NO2 conversion was investigated. A gas flow rate of 50cc/min with 250 ppm NO2 was used. The catalysts were characterized in terms of phase evolution on heat treatment by XRD and microstructure by SEM. Preliminary findings showed that increasing V2O5 composition led to the increase in removal of NO2. SEM analyses indicate that V2O5 loading up to 5% changed the microstructure of the catalyst to become more structured and porous favoring the reduction of NO and NO2.