Monolith Ce sub(0.6)sZr sub(0.35)O sub(2)-based catalysts for selective catalytic reduction of NO sub(x) with NH sub(3)

• Published in: Chemical engineering research & design Vol. 94; pp. 648 - 659
• Main Authors: Fang, Zhitao, Yuan, Bin, Lin, Tao, Xu, Haidi, Cao, Yi, Shi, Zhonghua, Gong, Maochu, Chen, Yaoqiang
• Format: Journal Article
• Language: English
• Published: 01-02-2015
• Subjects: Catalysis; Catalysts; Catalytic activity; Conversion; Oxidation; Selective catalytic reduction; Tungsten oxides; X-rays
• ISSN: 0263-8762; 1744-3563
• DOI: 10.1016/j.cherd.2014.10.006

The carrier material Ce sub(0.65)Zr sub(0.35)O sub(2) was prepared by the co-precipitation method and a series of Ce sub(0.65)Zr sub(0.35)O sub(2)-based monolith catalysts containing W, Fe or Cu were prepared for selective catalytic reduction (SCR) of NO sub(x) with NH sub(3). The catalysts were characterized by ammonia oxidation, N sub(2) adsorption-desorption, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and NH sub(3) temperature-programmed desorption (NH sub(3)-TPD). Catalytic activity tests reveal that catalyst WO sub(3)/Ce sub(0.65)Zr sub(0.35)O sub(2) has the best catalytic activity and a good resistance to hydrothermal aging. It is light-off at 200 [degrees]C and has the highest NO sub(x) conversion of 96% at 350 [degrees]C. The reaction window of 80% NO sub(x) conversion is in the temperature range of 241-457 [degrees]C with a gas hourly space velocity (GHSV) of 30,000 h super(-1). Moreover, it has a good SO sub(2) tolerance and good ability to fit the high GHSV, which suggests that it has a good prospect for real application. Characterization experiments show that WO sub(3)/Ce sub(0.65)Zr sub(0.35)O sub(2) 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 medium-strength acid. These characteristics are the main factors that lead to the increased SCR activity.