title: Enhancement of activity and sulfur resistance of CeO2 supported on TiO2-SiO2 for the selective catalytic reduction of NO by NH3.
abstract: A series of novel metal-oxide-supported CeO(2) catalysts were prepared via the wet impregnation method, and their NH(3)-SCR activities were investigated. The Ce/TiO(2)-SiO(2) catalyst with a Ti/Si mass ratio of 3/1 exhibited superior NH(3)-SCR activity and high N(2) selectivity in the temperature range of 250-450 °C. The characterization results revealed that the activity enhancement was correlated with the properties of the support material. Cerium was highly dispersed on the TiO(2)-SiO(2) binary metal oxide support, and the interaction of Ti and Si resulted in greater conversion of Ce(4+) to Ce(3+) on the surface of the catalyst compared to that on the single metal oxide supports. As a result of in the increased number of acid sites on Ce/TiO(2)-SiO(2) that resulted from the addition of SiO(2), the NH(3) adsorption capacity was significantly improved. All of these factors played significant roles in the high SCR activity. More importantly, Ce/TiO(2)-SiO(2) exhibited strong resistance to SO(2) and H(2)O poisoning. After the addition of SiO(2), the number of Lewis-acid sites was not decreased, but the number of Brønsted-acid sites on the TiO(2)-SiO(2) carrier was increased. The introduction of SiO(2) further weakened the alkalinity over the surface of the Ce/TiO(2)-SiO(2) catalyst, which resulted in sulfate not easily accumulating on the surface of the Ce/TiO(2)-SiO(2) catalyst in comparison with Ce/TiO(2).
authors.affiliation: State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Caixia
authors.initials: C
authors.lastname: Liu
authors.forename: Liang
authors.initials: L
authors.lastname: Chen
authors.forename: Junhua
authors.initials: J
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Ma
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Arandiyan
authors.forename: Yu
authors.initials: Y
authors.lastname: Du
authors.forename: Jiayu
authors.initials: J
authors.lastname: Xu
authors.forename: Jiming
authors.initials: J
authors.lastname: Hao
mesh_terms: D000327:Adsorption; D000641:Ammonia / Q000737:chemistry*; D002384:Catalysis; D002563:Cerium / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D056951:Photoelectron Spectroscopy; D016062:Porosity; D012822:Silicon Dioxide / Q000737:chemistry*; D013057:Spectrum Analysis; D013455:Sulfur / Q000737:chemistry*; D013458:Sulfur Dioxide / Q000737:chemistry; D013481:Superoxides / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: C507641:TiO2-SiO2; D013458:Sulfur Dioxide; D013481:Superoxides; D002563:Cerium; D009569:Nitric Oxide; C030583:ceric oxide; D013455:Sulfur; D012822:Silicon Dioxide; D000641:Ammonia; D014025:Titanium