High calcium resistance of CeO2-WO3 SCR catalysts: Structure investigation and deactivation analysis
High calcium resistance of CeO2-WO3 SCR catalysts: Structure investigation and deactivation analysis
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CeO2-WO3 SCR 催化剂的高抗钙性：结构研究和失活分析
DOI：
10.1016/j.cej.2017.02.027
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发表时间：
2017-06-01
影响因子：
15.1
通讯作者：
Hao, Jiming
中科院分区：
文献类型：
--
作者：
Li, Xiang;Li, Xiansheng;Hao, Jiming
制备了CaO中毒CeO 2-WO 3和V2 O 5-WO 3/TiO 2催化剂，并比较了其在NH3选择性催化还原NO（NH3-SCR）反应中的性能。结果表明，CeO 2-WO 3催化剂的抗钙性能优于V2 O 5-WO 3/TiO 2催化剂，当CaO质量分数达到5wt%时，其抗钙性能优于V2 O 5-WO 3/TiO 2催化剂。为了进一步了解催化剂的抗氧化机理，采用XRD、拉曼、XPS、H2-TPR、NH3-TPD和原位DRIFTS等手段对CeO 2-WO 3催化剂在CaO失活前后的变化进行了分析和探讨。结果表明，Ca物种的引入不仅影响了CeO 2的晶格结构，而且在表面形成了CaWO 4。此外，CaO的加入虽然增加了表面化学吸附的氧和Ce 4+物种的数量，但钝化后表面的还原位和刘易斯酸中心、NH3化学吸附量和Bronsted酸中心均受到极大的抑制。此外，碱性Ca物种的引入提高了催化剂对NO2的吸附能力，部分抵消了催化剂表面酸性中心损失的负面影响，这可能是CW催化剂比传统V2 O 5-WO 3/TiO 2催化剂具有更强抗CaO能力的主要原因。(C)2017爱思唯尔B. V.保留所有权利。
The SCR performances of CaO poisoning CeO2-WO3 and V2O5-WO3/TiO2 catalysts were prepared and compared for selective catalytic reduction of NO with NH3 (NH3-SCR). It was found that the CeO2-WO3 catalyst showed better calcium resistance than V2O5-WO3/TiO2 catalyst even when the CaO mass percentage reached up to 5 wt%. In order to further understand the resistance mechanism, XRD, Raman, XPS, H-2-TPR, NH3-TPD and in situ DRIFTS were used to analyze and explore the changes of CeO2-WO3 catalysts before and after the CaO deactivation. The results manifested that the introduction of Ca species not only affected CeO2 lattice but also led to CaWO4 formation on the surface. Additionally, although CaO increased the surface chemisorbed oxygen and Ce4+ species, the reducibility and Lewis acid sites, NH3 chemisorbed amount and Bronsted acid sites were greatly inhibited after deactivation. Furthermore, the enhanced NO2 adsorption capacity after the alkaline Ca species introduction could partially offset the negative effect in the loss of acid sites over the catalyst surface, which might be the primary reason for stronger CaO resistance of CW catalyst than traditional V2O5-WO3/TiO2 catalyst. (C) 2017 Elsevier B.V. All rights reserved.