Building concept inspired by raspberries: From microporous zeolite nanocrystals to hierarchically porous assemblies
Building concept inspired by raspberries: From microporous zeolite nanocrystals to hierarchically porous assemblies
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DOI：
10.1016/j.micromeso.2016.04.012
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发表时间：
2016-07
影响因子：
5.2
通讯作者：
M. Klumpp;Lintao Zeng;S. Al‐Thabaiti;A. Weber;W. Schwieger
中科院分区：
文献类型：
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作者：
M. Klumpp;Lintao Zeng;S. Al‐Thabaiti;A. Weber;W. Schwieger
分级多孔沸石在催化和吸附过程中提供了巨大的潜力，这是由于通过增加分子从本体相到最终活性位点或吸附位点的扩散性而增强的传质性质。在这篇文章中，我们提出了一个简单的，3步自下而上的制备路线，产生无粘合剂的球形沸石材料，表现出分级孔系统。该过程包括沸石合成、聚集和重结晶。在这方面的贡献，该过程是证明硅沸石-1（MFI型沸石）作为一个模型系统。聚集过程通过含有预合成纳米晶体的完整反应混合物的特殊喷雾干燥来实现。喷雾干燥方法产生球形聚集体，其含有源自沸石合成混合物的未转化部分的无定形二氧化硅物质，并且其充当中间粘合剂。然后应用蒸汽辅助结晶以将这些无定形物质转化为结晶沸石，使得整个方法能够利用来自沸石合成混合物的100%的初始硅。
Hierarchically porous zeolites offer great potential in catalytic and sorptive processes due to the enhanced mass transport properties by the increased diffusivity of the molecules from the bulk phase to the final active sites or sorption sites, respectively. In this contribution we present a simple, 3-step bottom-up preparation route yielding binder-free spherical zeolite material exhibiting a hierarchical pore system. This process consists of zeolite synthesis, aggregation and recrystallization. In this contribution, the process is demonstrated on silicalite-1 (MFI-type zeolite) as a model system. The aggregation process was realized by special spray drying of a complete reaction mixture containing pre-synthesized nanocrystals. The spray drying process results in spherical aggregates which contain amorphous silica species originating from the unconverted part of the zeolite synthesis mixture and which are acting as an intermediate binder. Steam-assisted crystallization was then applied to convert these amorphous species into crystalline zeolite enabling the overall process to utilize 100% of the initial silicon from the zeolite synthesis mixture.