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Honeycomb cordierite-based Mn-Ce/Al 2 O 3 catalysts were prepared by the impregnation method and used for low-temperature selective catalytic reduction (SCR) of NO x with NH 3 , with and without SO 2 and/or H 2 O in a homemade fixed-bed tubular reactor. The catalyst reached nearly 80% NO x conversion at 100 • C in the absence of SO 2 . However, SO 2 reduces the catalytic activity (80% to 72%) of the honeycomb cordierite-based Mn-Ce/Al 2 O 3 catalysts under identical conditions. This finding demonstrated that the catalyst exhibited high activity at low temperature and excellent SO 2 resistance in the presence of 50 ppm SO 2 . The fresh and sulfated honeycomb cordierite-based Mn-Ce/Al 2 O 3 catalysts were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), N 2 adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG-DTA), and Fourier transform infrared (FT-IR) spectroscopy. Characterization results indicated that the deactivation by SO 2 was primarily the result of the deposition of ammonium hydrogen sulfate and sulfated CeO 2 on the catalyst surface during the SCR process. The formed sulfates depressed the catalytic activity via the blocking of pores and the occupation of active sites. Additionally, the competitive adsorption between SO 2 and NH 3 always decreased the catalytic activity.

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