Highly Tunable Molecular Sieving and Adsorption Properties of Mixed-Linker Zeolitic Imidazolate Frameworks
Highly Tunable Molecular Sieving and Adsorption Properties of Mixed-Linker Zeolitic Imidazolate Frameworks
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DOI：
10.1021/jacs.5b00803
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发表时间：
2015-04-01
影响因子：
15
通讯作者：
Nair, Sankar
中科院分区：
文献类型：
--
作者：
Eum, Kiwon;Jayachandrababu, Krishna C.;Nair, Sankar
纳米多孔沸石咪唑盐框架（ZIFs）形成相当于沸石的结构拓扑结构。仅含一种咪唑连接体的zif对有限的分子对具有分离能力。我们发现，使用含有两种类型的连接剂的混合连接剂，zif的有效孔径、亲水性和亲有机性可以连续而大幅度地调整，从而使其成为更通用的分子分离平台。我们通过使用体积法、重量法和PFG-NMR方法，在具有大范围晶体尺寸（338 nm至120 μ m）的混合连接材料ZIF-8(x)-90（100-x）中对碳氢化合物、醇和水的吸附和扩散测量来说明这种显著的行为。核磁共振、粉末ft -拉曼光谱和微拉曼光谱明确地证实了单个ZIF晶体的混合连接性质。混合连接剂组成参数(x)的变化允许连续控制正丁烷、i-丁烷、丁醇和异丁醇的扩散率超过2-3个数量级，并控制水和醇的吸附，特别是在低活性下。
Nanoporous zeolitic imidazolate frameworks (ZIFs) form structural topologies equivalent to zeolites. ZIFs containing only one type of imidazole linker show separation capability for limited molecular pairs. We show that the effective pore size, hydrophilicity, and organophilicity of ZIFs can be continuously and drastically tuned using mixed-linker ZIFs containing two types of linkers, allowing their use as a more general molecular separation platform. We illustrate this remarkable behavior by adsorption and diffusion measurements of hydrocarbons, alcohols, and water in mixed-linker ZIF-8(x)-90(100-x) materials with a large range of crystal sizes (338 nm to 120 mu m), using volumetric, gravimetric, and PFG-NMR methods. NMR, powder FT-Raman, and micro-Raman spectroscopy unambiguously confirm the mixed-linker nature of individual ZIF crystals. Variation of the mixed-linker composition parameter (x) allows continuous control of n-butane, i-butane, butanol, and isobutanol diffusivities over 2-3 orders of magnitude and control of water and alcohol adsorption especially at low activities.