MnCeO_(x)/TiO_(2)has been widely used in selective catalytic reduction(SCR)of NO_(x)at low temperature.However,it is often poisoned in the presence of water vapor and sulfur dioxide.In this work,the promotion mechanis...MnCeO_(x)/TiO_(2)has been widely used in selective catalytic reduction(SCR)of NO_(x)at low temperature.However,it is often poisoned in the presence of water vapor and sulfur dioxide.In this work,the promotion mechanism of Ba modification was investigated.Results show that the doped BaO reacts with CeO_(2)and forms BaCeO_(3).This unique perovskite structure of BaCeO_(3)significantly enhances NO oxidation and NH_(3)activation of MnCeO_(x)/TiO_(2)catalyst so that the NO conversion and the resistances to SO_(2)improve.It is found that Ba species obviously promotes the NO adsorption ability and improve the redox properties of MnCeO_(x)/TiO_(2)catalyst.While the acid properties of the catalyst are inhibited by Ba modification and among which Lewis acid sites are dominant for both MnCeO_(x)/TiO_(2)and MnCe(Ba)O_(x)/TiO_(2)catalysts.Furthermore,in situ DRIFT experiments reveal that the NO reduction upon MnCeO_(x)/TiO_(2)and MnCe(Ba)O_(x)/TiO_(2)catalysts follows both E-R and L-H mechanisms,in which L-H is preferred.Ba species enhances the formation of active nitrate species,which accelerates the NO reduction through L-H mechanism.It is interesting that although Ba species weakens the NH_(3)adsorption,it induces the ammonia conversion to coordination ammonia,which in turn accelerates the catalytic reaction.展开更多
基金Project supported by National Natural Science Foundation of China(51772149)National Key Research and Development Program of China(2016YFC0205500)+1 种基金Qinglan Project of Jiangsu Province of China,Six Talent Peaks Project in Jiangsu Province(JNHB-044)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘MnCeO_(x)/TiO_(2)has been widely used in selective catalytic reduction(SCR)of NO_(x)at low temperature.However,it is often poisoned in the presence of water vapor and sulfur dioxide.In this work,the promotion mechanism of Ba modification was investigated.Results show that the doped BaO reacts with CeO_(2)and forms BaCeO_(3).This unique perovskite structure of BaCeO_(3)significantly enhances NO oxidation and NH_(3)activation of MnCeO_(x)/TiO_(2)catalyst so that the NO conversion and the resistances to SO_(2)improve.It is found that Ba species obviously promotes the NO adsorption ability and improve the redox properties of MnCeO_(x)/TiO_(2)catalyst.While the acid properties of the catalyst are inhibited by Ba modification and among which Lewis acid sites are dominant for both MnCeO_(x)/TiO_(2)and MnCe(Ba)O_(x)/TiO_(2)catalysts.Furthermore,in situ DRIFT experiments reveal that the NO reduction upon MnCeO_(x)/TiO_(2)and MnCe(Ba)O_(x)/TiO_(2)catalysts follows both E-R and L-H mechanisms,in which L-H is preferred.Ba species enhances the formation of active nitrate species,which accelerates the NO reduction through L-H mechanism.It is interesting that although Ba species weakens the NH_(3)adsorption,it induces the ammonia conversion to coordination ammonia,which in turn accelerates the catalytic reaction.
