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

Fe was used as the modifier to improve the performance of CeZr 2 O 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 CeZr 2 O x , along with the elevated resistance to SO 2 and H 2 O. The characterization results including BET, XRD, H 2 -TPR and NH 3 -TPD confirmed that Fe species in Fe 2 CeZr 2 O x catalyst could inhibit the formation of ZrO 2 crystals and lead to higher reducibility and surface acidity. In addition, more Ce 3+ and surface active oxygen species could be detected on Fe 2 CeZr 2 O x compared with CeZr 2 O x . By means of in situ DRIFT technique, it could be deduced that the SCR reaction process over Fe 2 CeZr 2 O x was accelerated mainly through theL–H pathway due to the advanced adsorption of NH 3 and NO x species, along with the promoted NO conversion to NO 2 . Therefore, the modification of CeZrO x catalyst by Fe had a significant stimulation effect on its low-temperature SCR performance.