Activity enhancement of sulphated Fe2O3 supported on TiO2–ZrO2 for the selective catalytic reduction of NO by NH3

Abstract Several Fe2O3.SO42−/(TiO2–ZrO2) catalysts with different ratios of Ti/Zr were prepared by wet impregnation method. The Fe2O3.SO42−/Ti1Zr4 (TiO2:ZrO2 = 1/4) exhibited the highest NOx conversions and N2 selectivity in 300–500 °C. And the SO2 resistance was well enhanced when TiO2 adding to ZrO2. The XRD, BET, H2-TPR, XPS, NH3-TPD, and DRIFTS characterization were conducted and it was concluded that the improvement of catalytic effect was closely related to the property’s enhancement when TiO2 adding to ZrO2. With the introducing TiO2, the surface area of carrier would be greatly enhanced, while Fe2O3 and SO42− highly dispersed on binary metal oxide (TiO2–ZrO2) supports, and the interaction between Ti and Zr would significantly lead to much more conversion of Fe3+ to Fe2+ on Ti1Zr4 support compared to TiO2 or ZrO2. A large number of Fe2+ might break a charge balance and accelerate to adsorb NH3 molecules or oxidize NO to NO2 in the SCR reaction. According to our DRIFTS results on FeS/(Ti1Zr4) catalyst, the introduction of TiO2 further improved the NH3 and NOx adsorption and activation over the surface of the Fe2O3.SO42−/(Ti1Zr4) catalysts, which might be the most important reason for Fe2O3.SO42−/(Ti1Zr4) catalyst possessed superior activity at high temperature.