Hierarchical nanofabrication of microporous crystals with ordered mesoporosity
Hierarchical nanofabrication of microporous crystals with ordered mesoporosity
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DOI：
10.1038/nmat2302
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发表时间：
2008-12-01
期刊：
影响因子：
41.2
通讯作者：
Tsapatsis, Michael
中科院分区：
文献类型：
--
作者：
Fan, Wei;Snyder, Mark A.;Tsapatsis, Michael
具有三维有序介孔（3DOm）特征的成型沸石纳米晶体和较大沸石颗粒对于制造薄的定向分子筛膜和实现新的选择性、分子可及和稳健的催化剂具有令人兴奋的技术意义。一个公认的手段，这种纳米颗粒和印迹材料的控制合成围绕模板的方法，但一个适当的通用模板的识别仍然难以捉摸。由于其高度互连的孔隙空间，有序的中孔碳复制品作为概念上有吸引力的材料用于进行沸石晶体的受限合成。在这里，我们展示了如何通过3DOm碳内的这种受限生长来实现广泛的晶体形态，该碳通过复制由尺寸可调（约10-40 nm）的二氧化硅纳米颗粒组成的胶体晶体来合成。这些模板内的受限晶体生长导致尺寸可调的、形状均匀的硅沸石-1纳米晶体以及3DOm印迹的单晶沸石颗粒。此外，新的晶体形态，从初级晶体颗粒的小面晶体生长物组成已被发现，提供了新的见解约束的晶体生长机制下的限制合成。
Shaped zeolite nanocrystals and larger zeolite particles with three-dimensionally ordered mesoporous (3DOm) features hold exciting technological implications for manufacturing thin, oriented molecular sieve films and realizing new selective, molecularly accessible and robust catalysts. A recognized means for controlled synthesis of such nanoparticulate and imprinted materials revolves around templating approaches, yet identification of an appropriately versatile template has remained elusive. Because of their highly interconnected pore space, ordered mesoporous carbon replicas serve as conceptually attractive materials for carrying out confined synthesis of zeolite crystals. Here, we demonstrate how a wide range of crystal morphologies can be realized through such confined growth within 3DOm carbon, synthesized by replication of colloidal crystals composed of size-tunable (about 10-40 nm) silica nanoparticles. Confined crystal growth within these templates leads to size-tunable, uniformly shaped silicalite-1 nanocrystals as well as 3DOm-imprinted single-crystal zeolite particles. In addition, novel crystal morphologies, consisting of faceted crystal outgrowths from primary crystalline particles have been discovered, providing new insight into constricted crystal growth mechanisms underlying confined synthesis.