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

作者：Farong Ji,Chenxu Li,Jianqiang Wang,Jun Wang,Meiqing Shen

摘要：A series of VOx/CeO2 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 NH3(NH3-SCR).The kinetic results show that VOx/CeO2 catalysts exhibit nearly constant apparent activation energies(Ea),indicating the same SCR reaction mechanism.The V-O-Ce bridging modes and oligomeric VOx were identified and quantified by Raman,FT-IR and H2-TPR.The amounts of the V-O-Ce bridging modes calculated by H2-TPR are correlated to the NH3-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 VOx/CeO2 catalysts.Therefore,it can be concluded that the V-O-Ce bridging modes are the active sites of VOx/CeO2 catalysts for the NH3-SCR reaction.

发文机构：Key Laboratory for Green Chemical Technology of State Education Ministry Collaborative Innovation Centre of Chemistry Science and Engineering（Tianjin） State Key Laboratory of Engines

关键词：SelectivecatalyticreductionVOx/CeO2catalystsV-O-CebridgingmodesActivesitesRareearths

分类号： X701[环境科学与工程—环境工程]O643.36[理学—物理化学]