Monolith Ce 0.65 Zr 0.35 O 2 -based catalysts for selective catalytic reduction of NO x with NH 3

a b s t r a c t The carrier material Ce0.65Zr0.35O2 was prepared by the co-precipitation method and a series of Ce0.65Zr0.35O2-based monolith catalysts containing W, Fe or Cu were prepared for selective catalytic reduction (SCR) of NOx with NH3. The catalysts were characterized by ammonia oxidation, N2 adsorption–desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and NH3 temperature-programmed desorption (NH3-TPD). Catalytic activity tests reveal that catalyst WO3/Ce0.65Zr0.35O2 has the best catalytic activity and a good resistance to hydrothermal aging. It is light-off at 200 ◦ C and has the highest NOx conversion of 96% at 350 ◦ C. The reaction window of 80% NOx conversion is in the temperature range of 241–457 ◦C with a gas hourly space velocity (GHSV) of 30,000 h−1. Moreover, it has a good SO2 tolerance and good ability to fit the high GHSV, which suggests that it has a good prospect for real application. Characterization experiments show that WO3/Ce0.65Zr0.35O2 has a weaker property of ammonia oxidation, a larger surface area, strong oxidation property with the highest binding energy of Ce, Zr and O, and the most surface mediumstrength acid. These characteristics are the main factors that lead to the increased SCR activity. © 2014 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.