以三种不同MOFs为前躯体的纳米催化剂的制备及其催化性能研究

发布时间：2018-05-15 18:17

本文选题：金属-有机框架化合物 + 前躯体　；参考：《新疆大学》2017年硕士论文

【摘要】：金属-有机框架化合物(MOFs)是一类由金属离子或金属簇通过有机配体三维方向有序无限连接,构筑出的一类多孔、大比表面积的配位聚合物。MOFs材料具有大比表面积和高孔隙率、规则的孔道以及结构和性质可调等特点,可将其应用于催化、气体存储、选择性分离、药物输送等领域。基于MOFs本身大的比表面积、丰富的碳源和金属源,将其用作前驱体,来合成具有纳米尺寸的多孔碳或金属化合物。本论文主要围绕以三种不同MOFs为前驱体或模板来合成具有独特结构的纳米新型催化剂材料,并根据相应复合物独特的结构特点,探索其在硝基化合物的还原等非均相催化领域的应用。具体工作如下:1.合成一种高效稳定且价格低廉的催化剂用于水体污染物对硝基苯酚(4-NP)的还原反应一直是科学家所关心的问题,而利用金属-有机骨架化合物作为前躯体或模板也是最近的研究热点。本章利用简单的自组装策略,通过氩气氛围下管式炉煅烧双金属-有机骨架材料Zn0.3Co2.7-ZIF前躯体来合成一种多孔的菱形十二面体催化剂Zn0.3Co2.7NC。当将此催化剂用于对硝基苯酚的还原反应时,仅5 min即可完成,且转化率几乎为100%,其反应速率常数为0.683 min-1,表现出优越的催化性能。另外,将其用于其他芳硝基化合物的还原反应,仍表现出优越的催化性能。将其反应速率常数与文献结果对比,均优于已有文献值。2.金属有机骨架(MOFs)材料,作为一种含无机和有机成分和具有扩展结构的配位键的杂化材料的结晶,已成为在凝聚态物质的研究中非常有吸引力的热点。如果起始原料、金属离子、短配体,Co配体,模板等,都是经过精心选择和正确组装入固体状态,那么磁耦合的组织和拓扑结构便可进一步被调整或控制合成。本章合成了一种钙钛矿型的催化剂前躯体[NH(CH3)][Co2+(COOH)],它由硝酸钴与甲酸、二甲胺在乙醇作溶剂下,静置陈化得到。在进一步的氩气氛围下热裂解,得到碳包覆的金属单质钴的骨架材料Co@NC作为催化剂,用于对硝基苯酚的还原反应,约16 min反应完成,且转化率几乎为100%,表现出较好的催化性能。在经过连续三次测试后,其表现出一定的可循环使用性能。3.FeCo纳米颗粒作为一个重要的磁性金属合金已被广泛利用,然而易氧化且有潜在的毒性,使其应用受到了很大的限制。因此,找到一种材料将FeCo纳米颗粒封装进去又不影响其本身性质,成为科学工作者一直探索的目标。本章合成了一种普鲁士蓝型的催化剂前躯体Co3[Fe(CN)6]2,在进一步的氩气氛围下热裂解,得到金属单质钴铁负载在氮掺杂碳的骨架材料CoFe@NC,以此作为催化剂用于对硝基苯酚(4-NP)的还原,约7 min反应完全,且转化率几乎为100%,表现出较好的催化性能。由于其具有较高的催化活性,有望在更广阔的催化领域得到应用。
[Abstract]:Metal-organic framework compound (MOFs) is a kind of coordination polymer. MOFs with large specific surface area and large specific surface area, which is composed of metal ions or metal clusters, which are connected by organic ligands in three dimensional direction, have large specific surface area and high porosity. Due to its regular pore and adjustable structure and properties, it can be used in the fields of catalysis, gas storage, selective separation and drug delivery. Based on the large specific surface area, abundant carbon and metal sources of MOFs, it is used as a precursor to synthesize porous carbon or metal compounds with nanometer size. In this thesis, three kinds of MOFs were used as precursors or templates to synthesize novel nano-catalyst materials with unique structure, and according to the unique structural characteristics of the corresponding complexes, Its applications in heterogeneous catalysis such as the reduction of nitro compounds were explored. The work is as follows: 1. The synthesis of a highly stable and inexpensive catalyst for the reduction of water pollutant p-nitrophenol 4-NPs has been a matter of concern to scientists. The use of metal-organic skeleton compounds as precursors or templates is also a hot topic. In this chapter, a porous diamond dodecahedral catalyst Zn0.3Co2.7NCwas synthesized by calcining bimetallic / organic skeleton Zn0.3Co2.7-ZIF precursor in argon atmosphere using a simple self-assembly strategy. When the catalyst was used in the reduction of p-nitrophenol, it was only 5 min, the conversion was almost 100kum, and the reaction rate constant was 0.683 min-1, which showed excellent catalytic performance. In addition, it still shows excellent catalytic performance when it is used in the reduction reaction of other aromatic nitro compounds. Compared with the results of literature, the reaction rate constant is better than the value of existing literature. 2. As a kind of hybrid material with inorganic and organic composition and extended structure, MOFs has become an attractive research hotspot in the field of condensed matter. If the starting materials, metal ions, short ligand Co ligands and templates are carefully selected and correctly assembled into the solid state, the structure and topology of magnetic coupling can be further adjusted or controlled. In this chapter, a perovskite-type catalyst [NH _ (NH _ (3) H _ (3)] [Co2 _ (COOH)] was synthesized, which was obtained by the static aging of cobalt nitrate with formic acid and dimethylamine in ethanol solvent. Under the condition of further pyrolysis in argon atmosphere, carbon coated metallic cobalt skeleton material Co@NC was obtained as catalyst for the reduction of p-nitrophenol. The reaction was completed at about 16 min, and the conversion rate was almost 100%, which showed good catalytic performance. After three successive tests, FeCo nanoparticles have been widely used as an important magnetic metal alloy. However, their applications are limited because of their oxidation and potential toxicity. Therefore, finding a material to encapsulate FeCo nanoparticles without affecting their own properties has been the goal of scientific researchers. In this chapter, a Prussian blue catalyst, Co3 [Fe(CN)6] 2, was synthesized and pyrolyzed in argon atmosphere to obtain the nitrogen-doped carbon skeleton material CoFeR NC, which was used as a catalyst for the reduction of p-nitrophenol 4-NPs. About 7 min reaction was complete and the conversion was almost 100%, which showed good catalytic performance. Because of its high catalytic activity, it is expected to be widely used in the field of catalysis.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36

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