title: Modification of CeO2-ZrO2 catalyst by potassium for NOx-assisted soot oxidation.
abstract: Potassium-modified ceria-zirconia catalyst was synthesized by wetness impregnation method. The ageing treatment was performed in static air at 800degrees C for 20 hr to evaluate the thermal stability of the catalyst. The catalysts were characterized by X-ray diffraction, BET surface area, oxygen storage capacity, NO(x)-temperature programmed desorption and soot-temperature programmed oxidation measurements. By introduction of potassium, the maximum soot oxidation rate temperature (T(m)) of the ceria-zirconia based catalyst decreased from 525 to 428 degrees C in the presence of NO under a loose contact mode. The shift of T(m) of the K-modified catalyst after ageing is only 15 degrees C. The enhanced activity of the aged catalyst mainly lies in the promotional effect of potassium on the NO(x)/oxygen storage capacity as well as the soot-catalyst contact.
authors.affiliation: State Key Laboratory of New Ceramics & Fine Process, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China. duanweng@tsinghua.edu.cn
authors.forename: Duan
authors.initials: D
authors.lastname: Weng
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Wu
authors.forename: Zhichun
authors.initials: Z
authors.lastname: Si
mesh_terms: D000327:Adsorption; D002245:Carbon Dioxide / Q000032:analysis; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry*; D009569:Nitric Oxide / Q000032:analysis; D010084:Oxidation-Reduction; D010100:Oxygen / Q000032:analysis; D011188:Potassium / Q000737:chemistry*; D053260:Soot / Q000737:chemistry*; D013696:Temperature; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry*
chemical_list: D009566:Nitrates; D053260:Soot; D002245:Carbon Dioxide; D002563:Cerium; D009569:Nitric Oxide; C030583:ceric oxide; D015040:Zirconium; D011188:Potassium; C028541:zirconium oxide; D010100:Oxygen