摘要：A series of x Ce-Fe/ZSM-5 ( x = 0, 0.25, 0.5 wt%) samples were prepared by the impregnation method, and the catalytic activity was evaluated by the selective catalytic reduction of NO x with ammonia (NH 3 -SCR). The physicochemical properties of prepared samples were characterized by various techniques such as X-ray diffraction (XRD), Brunner-Emmet-Teller (BET) measurement, hydrogen temperatureprogrammed reduction (H 2 -TPR), X-ray photoelectron spectroscopy (XPS), ammonia temperatureprogrammed desorption (NH 3 -TPD) and in situ diffuse reflectance infrared Fourier transform spectroscopy (in situ DRIFTS). XRD and BET results demonstrated that Ce and Fe species were uniform dispersed on the surface of the ZSM-5 zeolite and the micropore structure of ZSM-5 was still maintained. H 2 -TPR analysis indicated that the doping of Ce created more isolated Ce 4 and Fe 3 on the surface of catalysts, and the abundant Ce 4 and Fe 3 could enhance the reduction ability of catalysts. XPS analysis suggested that the doping of Ce could generate more oxygen vacancies, thereby increasing the number of chemisorption oxygen. According to the in-situ DRIFTS and NH 3 -TPD results, Ce species provided more acidic sites, which is beneficial to the NH 3 adsorption ability of ZSM-5 zeolite. Additionally, the abundant chemisorption oxygen, medium and strong Brønsted acid sites, excellent NH 3 adsorption ability and outstanding reduction property are beneficial to the NH 3 -SCR reaction. Among all prepared samples, the 0.25Ce-Fe/ZSM-5 sample possessed the widest reaction temperature window and the best catalytic performance (NO conversion over 98% at 350-450 °C), which was associated with the abundant acid sites and remarkable adsorption ability of NH 3 , outstanding redox ability and abundant chemisorption oxygen after the doping of Ce.
