纳米碳球的氢化、电化学性质及高温高压转变

发布时间：2018-04-09 02:35

本文选题：纳米碳球　切入点：氢化　出处：《吉林大学》2017年硕士论文

【摘要】：洋葱状富勒烯碳纳米球可看成由准球体同心壳层套构而成,具有优异的机械性能、良好的导电能力和化学稳定性以及独特的热学性质,可以广泛的应用于摩擦材料、电极材料、存储材料、超级电容器材料等各种领域。研究表明氢化的碳纳米球在某些方面的性能可以得到进一步提升,并且含氢量的高低对材料的性能会产生重要影响。因此,在探索简单高效制备氢化碳纳米球材料方法的同时,研究其生长机理并对氢化程度等参数进行可控调整,具有非常重要的科学意义和应用价值。本文中第一部分利用溶剂热合成的方法,针对上述科学问题展开了系统的研究。实验中以三氯甲烷作为碳源,金属钾作为还原剂,在100℃的温度环境下,利用金属钾较强的还原性,将三氯甲烷中的C-H键和C-Cl键进行断裂,一部分-Cl参与形成KCl,另一部分-Cl键与部分-H键结合形成HCl析出,剩余悬键重组形成含氢石墨片层,在经过不断卷曲包裹及团聚之后,最终形成了纳米尺寸并且含有一定氢化程度的球状结构。我们通过控制反应时间的长短,可以得到处于不同生长阶段的氢化碳纳米球样品,并对所合成的样品进行了详细的结构表征,通过对比实验系统研究了氢化碳纳米碳球生长过程中形貌与结构的改变,找到了样品氢化程度随反应时间的变化规律,为以后人们对纳米碳球材料的深入探索奠定了理论基础。电化学超级电容器作为一种新型的储能装置其性质处于充电电池和普通电容器之间,它具有充放电时间短,高比功率和长寿命等突出优点,具有重要的研究和应用价值。洋葱碳纳米球具有良好的导电能力和化学稳定性,并且在通过相应的处理后能够增大其内部的比表面积和孔径大小,从而使其电容量得到较大幅度的提升,是目前最具潜力的超级电容器电极材料之一。但由于制备处理工艺尚不成熟,处理的方法相对复杂,一直制约着洋葱碳纳米球作为超级电容材料的应用。本文的第二部分采用简单的火焰燃烧方法,以萘为碳源通过一步反应合成出另一种具有超高比电容量的洋葱碳纳米球,其初始电容可以达到77.4F/g。将初始样品放到管式炉中进行简单的高温处理,实现了通过控制温度增加洋葱碳纳米球的比表面积与孔径大小,进而提升电容容量。在温度达到450℃时,样品的比电容量提高到了181.7F/g,并且在经过500个恒流充放电周期后,依然能够保持90%以上的电容容量,展现了出了非常高的循环稳定特性。这种具有超高电容特性的碳纳米洋葱球原料来源广泛,合成方式与后续处理方法简单易行,具有广泛的实际应用前景。高温高压是材料合成领域中的重要方法,特别是在人工合成金刚石的过程中被广泛应用。洋葱碳纳米球作为一种特殊的碳材料,对其进行高温高压研究不但可以了解其高压高压下结构的改变与相变机制,更为人们探索新型碳材料提供了道路和方法。本论文对合成的富勒烯洋葱碳球进行了初步的高温高压研究,发现了富勒烯碳球在高温高压下会发生破碎和石墨化转变。
[Abstract]:Onion like fullerene carbon nanospheres can be regarded as quasi sphere by a set of concentric shell structure, with excellent mechanical properties, good electrical conductivity and chemical stability and unique thermal properties, can be widely used in friction materials, electrode materials, storage materials, super capacitor materials and other fields. The results show that the properties of carbon nanotube the ball hydrogenated in some aspects can be further improved, will have a significant impact and the level of hydrogen content on the performance of materials. Therefore, to explore the simple and efficient preparation method of hydrogenated carbon nanospheres and study the growth mechanism and controllable adjustment of parameters such as the degree of hydrogenation, which has very important scientific significance and the application value. This paper first part by solvothermal synthesis method, aiming at the scientific problems are researched. In the experiment by using chloroform as carbon source, Potassium metal as a reducing agent, at a temperature of 100 DEG C under the environment, the use of metal potassium strong reducibility, the chloroform in the C-H and C-Cl keys are broken, a part of -Cl involved in the formation of KCl, combined with another part of -Cl bond and -H bond forming part of HCl precipitation, the remaining dangling bonds containing hydrogen recombine to form graphite layer, after continuous crimp wraps and reunion, eventually formed a nanometer size and contains a certain degree of hydrogenation of globular structure. We by controlling the reaction time can be obtained in the hydrogenation of carbon nanometer ball samples in different growth stages, and the synthesized samples were characterized in detail. The morphology and structure of the growth process the change of hydrogenated carbon nano carbon spheres were studied through contrast experiment system, variation of sample degree of hydrogenation with reaction time were found for the deep exploration of the nano carbon ball material laid Theoretical basis. Electrochemical supercapacitor is a new energy storage device between the rechargeable battery and its properties in common capacitor, which has charge and discharge time is short, high power and long life and other advantages, has important research and application value. The onion nano carbon ball has good conductivity and chemical stability. And can increase the internal through after the processing of the surface area and pore size, so that the capacity is greatly improved, is one of the most promising electrode materials for supercapacitors. But because the preparation process is not mature, the processing method is relatively complex, has been restricting carbon onions nanosphere as the application of super capacitor materials. The second part of this paper uses a simple flame combustion method, using naphthalene as carbon source by a reaction to another with high specific capacitance The onion carbon nanospheres, the initial capacitance can reach 77.4F/g. the initial sample in high temperature treatment for simple tube furnace. The increase of onion carbon nanospheres by controlling the temperature of the surface area and pore size, and thus enhance the capacity of the capacitor. When the temperature reached 450 degrees, the sample specific capacitance increased to 181.7F/g, and after 500 charge discharge cycles, can still maintain the capacity of more than 90%, showing a stable circulation characteristic is very high. It has super high capacitance characteristics of carbon nano onion ball wide sources of raw materials, synthesis method and processing method is simple and has a broad application prospect at high temperature and high pressure is an important method in the field of material synthesis, especially is widely used in the process of synthetic diamond in onion. The carbon nano sphere as a special carbon material, the For high temperature and high pressure study can not only understand the change and transformation mechanism of the structure under high pressure, providing more people to explore the way and method of new carbon materials. This paper carried out a preliminary study on high temperature and high pressure synthesis of fullerene carbon onion ball, found the ball will change the broken carbon fullerene and graphitization under high temperature and high pressure.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1;O52;TM53

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