New insights into MnCe（Ba）Ox/TiO2 composite oxide catalyst:Barium additive accelerated ammonia conversion
来源期刊：JOURNAL OF RARE EARTHS2021年第5期
论文作者：Youchun Pan Qijie Jin Bingxu Lu Yan Ding Xin Xu Yuesong Shen Yanwei Zeng
摘 要：MnCeOx/TiO2 has been widely used in selective catalytic reduction（SCR） of NOx 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 CeO2 and forms BaCeO3.This unique perovskite structure of BaCeO3 significantly enhances NO oxidation and NH3 activation of MnCeOx/TiO2 catalyst so that the NO conversion and the resistances to SO2 improve.It is found that Ba species obviously promotes the NO adsorption ability and improve the redox properties of MnCeOx/TiO2 catalyst.While the acid properties of the catalyst are inhibited by Ba modification and among which Lewis acid sites are dominant for both MnCeOx/TiO2 and MnCe（Ba）Ox/TiO2 catalysts.Furthermore,in situ DRIFT experiments reveal that the NO reduction upon MnCeOx/TiO2 and MnCe（Ba）Ox/TiO2 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 NH3 adsorption,it induces the ammonia conversion to coordination ammonia,which in turn accelerates the catalytic reaction.
Youchun Pan1,2,3，Qijie Jin1,2,3，Bingxu Lu1，Yan Ding1，Xin Xu1，Yuesong Shen1,2,3，Yanwei Zeng1
1. College of Materials Science and Engineering,Nanjing Tech University2. Jiangsu Collaborative Innovation Center for Advanced Inorganic Function Composites,Nanjing Tech University3. Jiangsu National Synergetic Innovation Center for Advanced Materials,Nanjing Tech University
摘 要：MnCeOx/TiO2 has been widely used in selective catalytic reduction（SCR） of NOx 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 CeO2 and forms BaCeO3.This unique perovskite structure of BaCeO3 significantly enhances NO oxidation and NH3 activation of MnCeOx/TiO2 catalyst so that the NO conversion and the resistances to SO2 improve.It is found that Ba species obviously promotes the NO adsorption ability and improve the redox properties of MnCeOx/TiO2 catalyst.While the acid properties of the catalyst are inhibited by Ba modification and among which Lewis acid sites are dominant for both MnCeOx/TiO2 and MnCe（Ba）Ox/TiO2 catalysts.Furthermore,in situ DRIFT experiments reveal that the NO reduction upon MnCeOx/TiO2 and MnCe（Ba）Ox/TiO2 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 NH3 adsorption,it induces the ammonia conversion to coordination ammonia,which in turn accelerates the catalytic reaction.
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