Cerium doped copper/ZSM-5 catalysts used for the selective catalytic reduction of nitrogen oxide with ammonia
Cerium doped copper/ZSM-5 catalysts used for the selective catalytic reduction of nitrogen oxide with ammonia
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掺铈铜/ZSM-5催化剂用于氨选择性催化还原氮氧化物
DOI：
10.1016/j.cej.2015.02.004
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发表时间：
2015-06-15
影响因子：
15.1
通讯作者：
Hui, Kwansan
中科院分区：
文献类型：
--
作者：
Dou, Baojuan;Lv, Gang;Hui, Kwansan
具有不同铈负载量（0、0.5、1.0、1.5和2.0重量%）的CuCe/ZSM-5催化剂研究了NH3选择性催化还原（SCR）NO反应的结构特征与催化性能之间的相关性。结果表明，铈的加入增加了铜的分散，并阻止其结晶。X射线光电子能谱（XPS）和程序升温氢还原（H-2-TPR）结果表明，Cu物种在ZSM-5晶粒表面富集，部分Cu离子进入铈晶格。Ce的加入改善了CuCe/ZSM-5催化剂的氧化还原性能，这是由于Cu的价态和晶格氧的迁移率高于Cu/ZSM-5催化剂。因此，Ce的引入显著提高了Cu/ZSM-5催化剂的NO转化率。一方面，铈的引入增强了Cu-Z的低温活性。对于Cu-Z，在197 ℃左右达到95%的NO转化率，而对于CuCe 4-Z，相应的温度值降低到148 ℃。另一方面，当向Cu/ZSM-5中添加铈时，NO有效还原的温度范围（95%）也扩展到更高的温度。在所测试的Cu-Ce/ZSM-5催化剂中，CuCe 4-Z样品在148-427 ℃的温度范围内表现出最高的催化活性，以去除90%的NO。(C)2015爱思唯尔B. V.保留所有权利。
The CuCe/ZSM-5 catalysts with different cerium loadings (0, 0.5, 1.0, 1.5 and 2.0 wt.%) was investigated to evaluate the correlation between structural characteristics and catalytic performance for the selective catalytic reduction (SCR) of NO by NH3. It was found that the addition of cerium increased copper dispersion and prevented its crystallitation. According to the results of X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H-2-TPR), copper species were enriched on the ZSM-5 grain surfaces and part of copper ions was incorporated into the cerium lattice. Addition of cerium improved the redox properties of the CuCe/ZSM-5 catalysts, owing to the higher valence of copper and mobility of lattice oxygen than those of Cu/ZSM-5 catalyst. Hence the introduction of cerium in Cu/ZSM-5 improved significantly NO conversion. On the one hand, the cerium introduction into Cu-Z enhances their low-temperature activities. 95% NO conversion is reached around 197 degrees C for Cu-Z while the corresponding temperature value decreases to 148 degrees C for CuCe4-Z. On the other hand, the temperature range of efficient NO reduction (95%) also extends to higher temperature when the cerium are added to Cu/ZSM-5. Among the Cu-Ce/ZSM-5 catalysts tested, the CuCe4-Z sample exhibits the highest catalytic activity with the temperature range for 90% NO removal of 148-427 degrees C. (C) 2015 Elsevier B.V. All rights reserved.