New insights into the role of vanadia species as active sites for selective catalytic reduction of NO with ammonia over VO_x/CeO_2 catalysts |
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| Affiliation: | 1. Key Laboratory for Green Chemical Technology of State Education Ministry, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, PR China;2. School of Environment and safety Engineering, North University of China, Taiyuan 030051, PR China;3. State Key Laboratory of Engines, Tianjin University, Tianjin 300072, PR China;4. Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, PR China;5. State Key Laboratory of Advanced Technologies for Comprehensive Utilization of Platinum Metals, PR China;6. Wuxi Weifu Lida Catalytic Converter Co., Ltd., Wuxi 214028, PR China;1. School of Chemical Engineering & Technology, Key Laboratory for Green Chemical Technology of State Education Ministry, Tianjin University, Tianjin 300072, China;2. School of Environment and Safety Engineering, North University of China, Taiyuan 030051, China;3. Dezhou Graduate School of North University of China, Dezhou, China |
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| Abstract: | A series of VO_x/CeO_2 catalysts we re synthesized via vanadia supported on ceria with different BET surface areas.The catalysts were employed to investigate the active sites for the selective catalytic reduction of NO with NH_3(NH3-SCR).The kinetic results show that VO_x/CeO_2 catalysts exhibit nearly constant apparent activation energies(E_a),indicating the same SCR reaction mechanism.The V-O-Ce bridging modes and oligomeric VO_x were identified and quantified by Raman,FT-IR and H_2-TPR.The amounts of the V-O-Ce bridging modes calculated by H_2-TPR are correlated to the NH_3-SCR intrinsic reaction rates.The turnover frequencies(TOFs) show a constant value at the same temperature,which were calculated based on the number of V-O-Ce bridging modes of VO_x/CeO_2 catalysts.Therefore,it can be concluded that the V-O-Ce bridging modes are the active sites of VO_x/CeO_2 catalysts for the NH3-SCR reaction. |
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| Keywords: | Selective catalytic reduction V–O–Ce bridging modes Active sites Rare earths |
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