Sub-micron Cu/SSZ-13: Synthesis and application as selective catalytic reduction (SCR) catalysts
Sub-micron Cu/SSZ-13: Synthesis and application as selective catalytic reduction (SCR) catalysts
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DOI：
10.1016/j.apcatb.2016.08.053
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发表时间：
2017-02
影响因子：
22.1
通讯作者：
Sebastian Prodinger;M. Derewinski;Yilin Wang;N. Washton;E. Walter;J. Szanyi;F. Gao;Yong Wang
中科院分区：
文献类型：
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作者：
Sebastian Prodinger;M. Derewinski;Yilin Wang;N. Washton;E. Walter;J. Szanyi;F. Gao;Yong Wang
通过修改现有合成工艺获得的亚微米Cu/SSZ-13首次被证明是选择性催化还原NO的有效且稳定的催化剂。通过 X 射线衍射、N2 物理吸附和 27 Al MAS NMR 表征材料表明，模拟 SCR 反应条件的水热老化对于钠形式的较小颗粒更具破坏性。然而，Cu 交换后，Cu/SSZ-13 的催化性能和水热稳定性与粒径无关。特别是，在具有可比的 Al 和 Cu 含量的老化 Cu/SSZ-13 催化剂中，剩余四面体骨架 Al 和分离的 Cu 离子浓度之间存在明显的正相关性。这表明（1）孤立的Cu离子和配对的骨架Al构型表现出显着的水热稳定性； (2) 成对铝含量可以通过修改合成程序来改变，这似乎对在严酷的水热老化过程中稳定孤立的铜离子比颗粒尺寸具有更关键的影响。这项研究对于车辆脱硝技术的应用非常有意义，其中可以通过使用亚微米 Cu/SSZ-13 来实现涂层上活性物质的高负载量。
For the first time, sub-micron Cu/SSZ-13, obtained by modifying an existing synthesis procedure, was shown to be an effective and stable catalyst for selective catalytic reduction of NO. Characterization of the materials with X-ray diffraction, N2-physisorption and27Al MAS NMR shows that hydrothermal aging, which simulates SCR reaction conditions, is more destructive for smaller particles in a sodium form. After Cu exchange, however, the catalytic performance and hydrothermal stability for Cu/SSZ-13 is independent of the particle size. In particular, a clear positive correlation is found between remaining tetrahedral framework Al and isolated Cu-ion concentrations in aged Cu/SSZ-13 catalysts of comparable Al and Cu contents. This indicates that (1) isolated Cu-ion and paired framework Al configurations display remarkable hydrothermal stabilities; and (2) paired-Al contents can be varied via modifying the synthesis procedures, which appear to have a more critical influence on stabilizing isolated Cu-ions during harsh hydrothermal aging than the particle size. This study is of high interest for applications in vehicular DeNOx technologies where high loadings of active species on wash coats can be achieved by using sub-micron Cu/SSZ-13.