Design and synthesis of core-shell structured meso-Cu-SSZ-13@mesoporous aluminosilicate catalyst for SCR of NOx with NH3: Enhancement of activity, hydrothermal stability and propene poisoning resistance
Design and synthesis of core-shell structured meso-Cu-SSZ-13@mesoporous aluminosilicate catalyst for SCR of NOx with NH3: Enhancement of activity, hydrothermal stability and propene poisoning resistance
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DOI：
10.1016/j.apcatb.2016.04.058
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发表时间：
2016-10
影响因子：
22.1
通讯作者：
Tao Zhang;F. Qiu;Junhua Li
中科院分区：
文献类型：
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作者：
Tao Zhang;F. Qiu;Junhua Li
首先通过控制脱硅与随后的自组装相结合来合成具有介孔铝硅酸盐（MAS）壳和含介孔的SSZ-13（meso-SSZ-13）核的核-壳结构复合材料。随后通过铜离子交换法制备相应的催化剂。该催化剂可同时解决现有柴油机尾气NOx排放控制Cu-SSZ-13催化剂存在的三大问题，低温活性、水热稳定性和抗丙烯中毒性。与Cu-SSZ-13相比，meso-Cu-SSZ-13@mosporous aluminosilicate（meso-Cu-SSZ-13@MAS）催化剂在整个温度范围内表现出更高的SCR活性。观察到这种增加是由于增加了活性Cu物质（分离的Cu2+离子）的量和更少的孔扩散限制。具有"碎石混凝土"状介观结构的MAS壳层可以有效地防止介孔分子筛SSZ-13核的脱铝，从而提高了介孔分子筛Cu-SSZ-13@MAS催化剂的水热稳定性。此外，meso-Cu-SSZ-13@MAS表现出更高的抗烃中毒性，因为其外表面具有较少的丙烯氧化反应的活性位点。
A core-shell structured composite material with a mesoporous aluminosilicate (MAS) shell and mesopore-containing SSZ-13 (meso-SSZ-13) core was first synthesized by combining controlled desilication with subsequent self-assembly. The corresponding catalyst was subsequently prepared by a copper ion-exchange method. This catalyst can simultaneously solve three major problems existing in the previous Cu-SSZ-13 catalyst for NOxemission control from diesel engine exhaust, i.e., low temperature activity, hydrothermal stability and propene poisoning resistance. In comparison with Cu-SSZ-13, themeso-Cu-SSZ-13@mesoporous aluminosilicate (meso-Cu-SSZ-13@MAS) catalyst showed higher SCR activity across the entire temperature range. This increase was observed due to increasing the amount of active Cu species (isolated Cu2+ions) and fewer pore diffusion limitations. The MAS shell with a “concrete with crushed stone”-like mesostructure could prevent the dealumination ofmeso-SSZ-13 core effectively, and therefore enhanced the hydrothermal stability of themeso-Cu-SSZ-13@MAS catalyst. Additionally,meso-Cu-SSZ-13@MAS exhibited higher hydrocarbon poisoning resistance because its external surface has fewer active sites for propene oxidation reaction.