The promotion effect of Fe on CeZr2O x catalyst for the low-temperature SCR of NO x by NH3

Abstract

Fe was used as the modifier to improve the performance of CeZr2O x catalyst for the selective catalytic reduction (SCR) reaction with ammonia. Experimental results revealed that proper Fe species (Fe/Ce molar ratio = 2) could effectively improve the SCR activity of CeZr2O x , along with the elevated resistance to SO2 and H2O. The characterization results including BET, XRD, H2-TPR and NH3-TPD confirmed that Fe species in Fe2CeZr2O x catalyst could inhibit the formation of ZrO2 crystals and lead to higher reducibility and surface acidity. In addition, more Ce3+ and surface active oxygen species could be detected on Fe2CeZr2O x compared with CeZr2O x . By means of in situ DRIFT technique, it could be deduced that the SCR reaction process over Fe2CeZr2O x was accelerated mainly through theL–H pathway due to the advanced adsorption of NH3 and NO x species, along with the promoted NO conversion to NO2. Therefore, the modification of CeZrO x catalyst by Fe had a significant stimulation effect on its low-temperature SCR performance.