Introduction manner of sulfate acid for improving the performance of SO42−/CeO2 on selective catalytic reduction of NO by NH3

A series of sulfated CeO 2 catalysts were synthesized by impregnation and sol-gel methods and used for selective catalytic reduction (SCR) of NO x by NH 3 . The results showed that the sulfated CeO 2 catalysts prepared by sol-gel method showed excellent catalytic activity at 150–450 °C, and more than 90% NO x conversion was obtained at 232–450 °C with a gas hourly space velocity of 60000 h −1 . The catalysts were characterized by X-ray diffraction (XRD), N 2 adsorption, Raman, thermogravimetry (TG), H 2 -temperature-programmed reduction (H 2 -TPR) and Py-infrared spectroscopy (Py-IR). The excellent SCR performance was associated with the surface acidity and the micro-structure. The introduction of sulfate acid into CeO 2 could increase the amount of Bronsted and Lewis acid sites over the catalysts, resulting in the improvement of the low temperature activity. The sulfated CeO 2 catalysts prepared by sol-gel method possessed lower crystallization degree, excellent redox property and larger specific surface areas, which were responsible for the superior SCR performance.