Selective catalytic reduction of nitric oxide with ammonia over high-activity Fe/SSZ-13 and Fe/one-pot-synthesized Cu-SSZ-13 catalysts

Fe/SSZ-13 and Fe/one-pot-synthesized Cu-SSZ-13 catalysts were prepared by a simple incipient wetness impregnation (I.W.I.) method. These Fe-impregnated catalysts showed higher catalytic activities for the selective catalytic reduction (SCR) of NO with ammonia as compared to other high-activity catalysts that were prepared by the ion-exchange (I.E.) method, such as Fe-SSZ-13, Cu-SSZ-13 and one-pot-synthesized Cu-SSZ-13. These Fe-impregnated catalysts also exhibited higher SO₂ resistance and yielded lower N₂O product concentrations. The catalysts were characterized by XRD, XPS, ESR, H₂-TPR and ICP. The XPS and H₂-TPR results indicated that the lower oxidation-state Fe which existed in the Fe-impregnated sample via incipient wetness impregnation was beneficial for the NH₃-SCR activity.