Enhancement of Activity and Sulfur Resistance of CeO2 Supported on TiO2鈥揝iO2 for the Selective Catalytic Reduction of NO by NH3

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• 作者：Caixia Liu ; Liang Chen ; Junhua Li ; Lei Ma ; Hamidreza Arandiyan ; Yu Du ; Jiayu Xu ; Jiming Hao
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：June 5, 2012
• 年：2012
• 卷：46
• 期：11
• 页码：6182-6189
• 全文大小：483K
• 年卷期：v.46,no.11(June 5, 2012)
• ISSN：1520-5851

文摘

A series of novel metal-oxide-supported CeO₂ catalysts were prepared via the wet impregnation method, and their NH₃鈥揝CR activities were investigated. The Ce/TiO₂鈥揝iO₂ catalyst with a Ti/Si mass ratio of 3/1 exhibited superior NH₃鈥揝CR activity and high N₂ selectivity in the temperature range of 250鈥?50 掳C. The characterization results revealed that the activity enhancement was correlated with the properties of the support material. Cerium was highly dispersed on the TiO₂鈥揝iO₂ binary metal oxide support, and the interaction of Ti and Si resulted in greater conversion of Ce⁴⁺ to Ce³⁺ 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/TiO₂鈥揝iO₂ that resulted from the addition of SiO₂, the NH₃ adsorption capacity was significantly improved. All of these factors played significant roles in the high SCR activity. More importantly, Ce/TiO₂鈥揝iO₂ exhibited strong resistance to SO₂ and H₂O poisoning. After the addition of SiO₂, the number of Lewis-acid sites was not decreased, but the number of Br酶nsted-acid sites on the TiO₂鈥揝iO₂ carrier was increased. The introduction of SiO₂ further weakened the alkalinity over the surface of the Ce/TiO₂鈥揝iO₂ catalyst, which resulted in sulfate not easily accumulating on the surface of the Ce/TiO₂鈥揝iO₂ catalyst in comparison with Ce/TiO₂.