以氢氧化锌纳米结构为前躯体的金属有机框架膜的制备及性能研究

发布时间：2018-11-06 10:07

【摘要】：金属有机框架材料(MOFs)是一种新型的多孔晶体材料,具有规则的孔洞结构、高的孔隙率和大的比表面积、结构和性质的多样性和可调性等特点,使得由其制成的薄膜,在气体分离、气敏传感、薄膜催化等领域具有重要应用。但是,当前MOF膜的制备存在异质成核困难、高能耗、使用昂贵有机溶剂和易产生缺陷裂纹等问题。因此,我们探索利用氢氧化锌纳米结构作为金属前躯体,发展一种简单有效经济环保的制备Zn-MOF膜的新方法。主要内容为：1.首先利用氢氧化锌纳米结构作为前躯体,制备了致密的MOF-5膜。同时发现对苯二甲酸除了作为配体之外,还能起到封端剂的作用,获得了不同形貌的ZnO六方微晶,并研究了其生长机制和光致发光性能。2.利用氢氧化锌纳米结构作为唯一锌源,在室温下,水和乙醇溶剂中,合成了厚度约为800 nm,连续的ZIF-8膜。氢氧化锌纳米结构还表现了明显的结构导向作用。这种方法具有很好的通用性,适宜规模化生产。3.将以氢氧化锌纳米结构为前躯体获得的ZIF-8膜作为晶种,经过二次生长获得了形貌更好,厚度约为2.5μm的ZIF-8膜。将其用于单组分气体分离性能研究,H2/CO2, H2/N2和H2/CH4的理想分离因子分别为3.58,12.53和9.76,远大于Knudsen分离因子,其中H2的通量约为47.14*10-7 mol·m-2·s-1·Pa-1,并且表现了很好的可重复性和持久性。
[Abstract]:Organometallic frame material (MOFs) is a new porous crystalline material with regular pore structure, high porosity and large specific surface area, diversity of structure and properties, and tunability. It has important applications in gas separation, gas sensing, film catalysis and so on. However, the preparation of MOF films is difficult to nucleate heterogeneity, high energy consumption, the use of expensive organic solvents and easy to produce defects and cracks. Therefore, we have explored a new method of preparing Zn-MOF membrane by using zinc hydroxide nanostructure as metal precursor and developing a simple, economical and environmentally friendly method. The main contents are as follows: 1. A compact MOF-5 film was prepared by using zinc hydroxide nanostructure as precursor. It was also found that terephthalic acid could also act as a capping agent in addition to being a ligand. Different morphologies of ZnO hexagonal microcrystals were obtained. The growth mechanism and photoluminescence properties were studied. 2. Using zinc hydroxide nanostructure as the sole zinc source, a continuous ZIF-8 film with a thickness of about 800 nm, was synthesized at room temperature in water and ethanol solvent. Zinc hydroxide nanostructures also exhibit obvious structural orientation. This method has good versatility and is suitable for large-scale production. The ZIF-8 film obtained from zinc hydroxide nanostructure as the precursor was used as seed, and the ZIF-8 film with a thickness of about 2.5 渭 m was obtained by secondary growth. The ideal separation factors of H _ 2 / CO _ 2, H2/N2 and H2/CH4 were 3.58% 12.53 and 9.76, respectively, which were much higher than those of Knudsen. The H _ 2 flux is about 47.14 ~ (- 7) mol m ~ (-2) s ~ (-1) Pa-1, and has good repeatability and persistence.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;O627

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