大管径碳纳米管及碳包覆金属材料的制备研究

发布时间：2018-04-05 06:38

本文选题：大管径多孔碳纳米管　切入点：碳包覆　出处：《河南大学》2015年硕士论文

【摘要】：碳纳米管具有优异的电学性能、力学性能和热学性能,使其在超级电容器、功率电子器件、增强材料和散热材料有着广泛的应用,目前,碳纳米管在超级电容器中的应用已经成为研究的热点,这是因为碳纳米管所特有的管状结构使它有利于电解液离子的传输,而大管径多孔碳纳米管(Large-diameter and porous CNTs,LPCNTs)可利用其管径大、具有孔洞结构的优点,使其在作为电极材料,催化剂载体等方面具有优势。传统碳纳米管的制备方法,往往所得到的碳纳米管管径只有几十纳米,目前,碳纳米管的制备主要以CVD方法为主,但其制备的碳纳米管往往管径较小,石墨化程度低,且含有许多杂质,这使其在实际应用中受到了限制。另外,碳材料优异的化学稳定性使其具有保护材料化学稳定性的特性。碳包覆磁性纳米材料作为一类新型的纳米复合材料,其碳包覆层能够使金属纳米颗粒免受外界环境的侵蚀而保持其固有的性质,并具有更好的导电性和生物相容性。基于以上情况,本论文开展了以多元醇为碳源制备LPCNTs方法学的研究,并制备出钴镍纳米棒(Cobalt-nickel nanorods,Co Ni-nanorods)、钴纳米球(Cobalt nanoballs,Co-nanoballs),随后通过一种简单易行的方法对Co Ni-nanorods、Co-nanoballs完成碳包覆过程。具体工作如下:(1)在温和条件下采用低温渗碳法将碳原子引入到镍纳米线(Ni-Nanowires,Ni-NWs)中,通过高温加热,使碳原子转移到Ni-NWs表面形成碳层,完成碳包覆过程,随后用稀盐酸将“核”Ni-NWs去除,最终得到LPCNTs。通过XRD与TEM表征,证明该方法可以有效的通过渗碳反应引入碳原子,并且成功的通过高温加热使碳镍分离,从而在Ni-NWs表面形成碳层。所得LPCNTs直径主要集中在400-600nm之间,比电容为74F/g。(2)以无水氯化钌为诱导剂,制备出Co Ni-nanorods,研究了不同钴镍摩尔比对Co Ni-nanorods形貌的影响,所制备的Co Ni-nanorods长度约为35nm-50nm,两端宽度约为8nm,中间部分宽度约为4nm,并采用一种简单快捷的方法对其完成碳包覆过程。通过VSM测试对其磁性能进行表征,其饱和磁场强度可达60.1emu.g-1。(3)采用水合肼还原法制备出Co-nanoballs,并对其完成碳包覆过程,实验中通过控制反应时间可简单有效的控制其碳层厚度。我们用TEM和Raman图谱分析了碳层的结晶性,并测试了所制备的钴纳米球的饱和磁场强度及其矫顽力大小。
[Abstract]:Carbon nanotubes have excellent electrical properties, mechanical properties and thermal properties, the super capacitor, power electronic devices, materials and enhance the heat dissipation materials have been widely used, the application of carbon nanotubes in super capacitor has become a hot research topic. This is because of the unique tubular structure of carbon nanotubes. It is conducive to the transmission of electrolyte, and large diameter porous carbon nanotubes (Large-diameter and porous CNTs, LPCNTs) can use its large diameter, has the advantages of pore structure, which has advantages as the electrode materials, catalyst carrier and so on. The traditional preparation methods of carbon nanotubes, carbon nano tube diameter are often at present, only a few tens of nanometers, the carbon nanotubes prepared by CVD method, but the preparation of carbon nanotubes are smaller pipe diameter, the graphitization degree is low, and contains many impurities, which make it In the practical application is limited. In addition, the chemical stability of carbon materials due to its excellent characteristics of protective material chemical stability. Carbon coated magnetic nano materials as a new type of nano composite materials, the properties of carbon coated layer can make metal nano particles from erosion of the external environment and maintain its inherent compatibility, conductive and biological and better. Based on the above situation, this paper studied the preparation method of carbon source LPCNTs to polyols, and preparation of cobalt nickel nanorods (Cobalt-nickel nanorods, Co Ni-nanorods), cobalt nanoparticles (Cobalt nanoballs, Co-nanoballs), followed by a simple method of Co Ni-nanorods, Co-nanoballs to complete the carbon coating process. The specific work is as follows: (1) under mild conditions by low temperature carburizing carbon atoms into the nickel nanowires (Ni-Nanowires, Ni-NWs), by High temperature heating, the carbon atom transfer to the Ni-NWs layer formed on the surface of carbon, carbon coated finish process, then the "core" of Ni-NWs removal with dilute hydrochloric acid, obtained by XRD LPCNTs. and TEM characterization, prove that the method can effectively introduce carbon atoms by carburizing reaction, and succeeded by heating the carbon and nickel separation. The formation of carbon layer on the surface of Ni-NWs. The diameter of LPCNTs is mainly concentrated in the 400-600nm, the specific capacitance was 74F/g. (2) with anhydrous ruthenium chloride as inducer, prepared by Co Ni-nanorods, to study the effects of cobalt and nickel Co molar ratio on the morphology of Ni-nanorods, prepared by the Co Ni-nanorods length is about 35nm-50nm, width of both ends the middle part is 8nm, width is about 4nm, and the use of a simple and quick method to complete the process of the carbon coating was characterized by VSM. The test on the magnetic properties, the saturation magnetic field intensity can be up to 60.1emu.g-1. (3) Co-nanoballs prepared by hydrazine reduction method, and the complete carbon coating process, the experiment can be simple and effective to control the thickness of carbon layer by controlling the reaction time. We use TEM and Raman analysis of crystalline carbon layer, and tested the cobalt nanoparticles prepared by the saturation magnetic field intensity and coercive the size of the force.

【学位授予单位】：河南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TQ127.11

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