NOx Storage and Reduction Properties of Model Ceria-based Lean NOx Trap Catalysts
NOx Storage and Reduction Properties of Model Ceria-based Lean NOx Trap Catalysts
复制标题
DOI：
10.1016/j.apcatb.2012.02.028
复制
发表时间：
2012-05
影响因子：
22.1
通讯作者：
C. Shi;Yaying Ji;U. Graham;G. Jacobs;M. Crocker;Zhao-shun Zhang;Yu Wang;T. Toops
中科院分区：
文献类型：
--
作者：
C. Shi;Yaying Ji;U. Graham;G. Jacobs;M. Crocker;Zhao-shun Zhang;Yu Wang;T. Toops
制备了Pt/Ba/CeO_2、Pt/CeO_2/Al_2O_3和Pt/BaO/CeO_2/Al_2O_3三种含CeO_2的LNT模型催化剂，并与标准的Pt/BaO/Al_2O_3型LNT催化剂进行了比较。在这些催化剂中，二氧化铈用作NOx储存组分和/或载体材料。考察了氧化铈对催化剂微观结构的影响，以及氧化铈对催化剂的NOx储存能力、再生性能和贫/富循环性能的影响。Pt/Ba/CeO 2和Pt/BaO/CeO 2/Al 2 O3催化剂在200 ° C和300°C下的NOx存储容量均高于Pt/BaO/Al 2 O3催化剂，但后者在400°C下的NOx存储容量更高。TPR测试结果表明，氧化铈的加入改善了催化剂的低温再生性能。这些因素有助于Pt/Ba/CeO 2和Pt/BaO/CeO 2/Al 2 O3催化剂在200-300°C循环条件下表现出上级NOx储存-还原性能。总的来说，Pt/BaO/CeO 2/Al 2 O3（其显示出良好平衡的NOx储存和再生行为）显示出最佳性能，在贫-富循环条件下在200-400°C的温度范围内提供一致的高NOx转化水平。
Three kinds of model ceria-containing LNT catalysts, corresponding to Pt/Ba/CeO2, Pt/CeO2/Al2O3and Pt/BaO/CeO2/Al2O3, were prepared for comparison with a standard LNT catalyst of the Pt/BaO/Al2O3type. In these catalysts ceria functioned as a NOxstorage component and/or a support material. The influence of ceria on the microstructure of the catalysts was investigated, in addition to the effect on NOxstorage capacity, regeneration behavior and catalyst performance during lean/rich cycling. The Pt/Ba/CeO2and Pt/BaO/CeO2/Al2O3catalysts exhibited higher NOxstorage capacity at 200 and 300°C relative to the Pt/BaO/Al2O3catalyst, although the latter displayed better storage capacity at 400°C. Catalyst regeneration behavior at low temperature was also improved by the presence of ceria, as reflected by TPR measurements. These factors contributed to the superior NOxstorage-reduction performance exhibited by the Pt/Ba/CeO2and Pt/BaO/CeO2/Al2O3catalysts under cycling conditions in the temperature range 200–300°C. Overall, Pt/BaO/CeO2/Al2O3(which displayed well balanced NOxstorage and regeneration behavior), showed the best performance, affording consistently high NOxconversion levels in the temperature range 200–400°C under lean-rich cycling conditions.