Deactivation Mechanism of Potassium on the V2O5/CeO2 Catalysts for SCR Reaction: Acidity, Reducibility and Adsorbed-NOx

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• 作者：Yue Peng ; Junhua Li ; Xu Huang ; Xiang Li ; Wenkang Su ; Xiaoxu Sun ; Dezhi Wang ; Jiming Hao
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：April 15, 2014
• 年：2014
• 卷：48
• 期：8
• 页码：4515-4520
• 全文大小：451K
• 年卷期：v.48,no.8(April 15, 2014)
• ISSN：1520-5851

文摘

A series of V<sub>2sub>O<sub>5sub>/CeO<sub>2sub> catalysts with different potassium loadings were prepared to investigate alkali deactivations for selective catalytic reduction of NO<sub>xsub> with NH<sub>3sub>. An alkali poisoning mechanism could be attributed to surface acidity, reducibility, and NO<sub>xsub> adsorption/desorption behaviors. The detailed factors are as follows: (1) decrease of surface acidity suppresses NH<sub>3sub> adsorption by strong bonding of alkali to vanadia (major factor); (2) low reducibility prohibits NH<sub>3sub> activation and NO oxidation by formation bonding of alkali to vanadia and ceria (important factor); (3) active NO<sub>xsub><sup>鈥?/sup> species at low temperature diminish because of coverage of alkali on the surfaces (minor factor); and (4) stable, inactive nitrate species at high temperature increase by generating new basic sites (important factor).