化学气相沉积法制备分枝状碳纳米管及其复合材料的研究
发布时间：2018-11-28 21:14
【摘要】： 碳纳米管由于其独特的物理化学性能和潜在应用价值,引起了科学界广泛关注。本文研究了以二甲硫醚为碳源,以Co/MgO为催化剂,采用化学气相沉积法制备碳纳米管的方法;探究各种实验参数,如反应温度、气体流量等因素对碳纳米管生长过程的影响;系统地研究了分枝状碳纳米管的形核及生长机制,实现了分枝状碳纳米管的可控制备;研究了二甲硫醚的浓度对Co_9S_8纳米线填充碳纳米管产物的形貌和结构的影响以及填充机理,发现了工艺简单、反应可控性较好的Co_9S_8纳米线填充碳纳米管的制备方法。主要研究结果如下: 1.采用催化裂解二甲硫醚制备了碳纳米管,实验发现产物对温度很敏感,通过对比实验发现合适的反应温度为1000°C;二甲硫醚蒸汽的浓度和流量对产物的产量和形貌也有很大影响,当二甲硫醚的浓度很高时,大量的碳原子覆盖在催化剂的表面,导致催化剂的活性降低,此时产物为很短的碳纳米管或碳纳米纤维,且其石墨化程度很低,而当二甲硫醚的浓度较低时,产物比较少且石墨化程度也很低。碳纳米管生长的最佳二甲硫醚浓度范围为:3.36-5.48%。二甲硫醚流量较大时有大量分枝状碳纳米管生成,这些分枝状碳纳米管有很长的分支,在纳米器件领域有很大的应用潜力,而当二甲硫醚流量较小时,产物较少。对分枝状碳纳米管的生长机理也进行了研究,并提出了一个简单的生长模型。 2.采用化学气相沉积法制备出了碳纳米管及Y形碳纳米管产物,碳纳米管直径分布在30~70nm范围内,其中Y形碳纳米管外径约为60~70nm,内径约为30~40nm。通过SEM、TEM、Raman、XRD对产品的形态与结构进行表征分析,结果显示所制得碳纳米管石墨化程度比较高,产品纯度也较高。对单根Y形碳纳米管的三个分支的导电性能进行了测试,结果表明所测试的Y形碳纳米管具有类似于金属性的导电性能。 3.制得了Co_9S_8纳米线填充碳纳米管,影响Co_9S_8纳米线填充碳纳米管的关键因素为二甲硫醚的浓度,二甲硫醚不但提供碳源,也提供Co_9S_8填充碳纳米管过程中必不可少的硫源。实现Co_9S_8纳米线填充碳纳米管的二甲硫醚最佳浓度范围为1.26%-1.47%。当二甲硫醚的浓度高于1.47%时,产物中有Y形碳纳米管生成;二甲硫醚浓度低于1.26%时,产物为中空的短碳纳米管。Co_9S_8纳米线填充碳纳米管的生长机制为“催化剂原位转变诱导碳纳米管填充”。
[Abstract]:Carbon nanotubes (CNTs) have attracted wide attention due to their unique physical and chemical properties and potential application value. In this paper, the method of preparing carbon nanotubes by chemical vapor deposition with dimethyl sulfide as carbon source and Co/MgO as catalyst was studied, and the effects of various experimental parameters, such as reaction temperature and gas flow rate, on the growth process of carbon nanotubes were investigated. The nucleation and growth mechanism of branched carbon nanotubes (CNTs) were studied systematically, and the controllable preparation of branched CNTs was realized. The effect of the concentration of dimethyl sulfide on the morphology and structure of carbon nanotubes filled with Co_9S_8 nanowires and the filling mechanism were studied. Preparation of Co_9S_8 nanowires filled with carbon nanotubes with good controllability. The main results are as follows: 1. Carbon nanotubes (CNTs) were prepared by catalytic pyrolysis of dimethyl sulfide. The results showed that the product was sensitive to temperature and the appropriate reaction temperature was 1000 掳C by comparison. The concentration and flow rate of dimethyl sulfide vapor also have a great influence on the yield and morphology of the product. When the concentration of dimethyl sulfide is very high, a large number of carbon atoms cover the surface of the catalyst, which results in the decrease of catalyst activity. The products are short carbon nanotubes or carbon nanofibers, and their graphitization degree is very low, but when the concentration of dimethyl sulfide is lower, the products are less and the degree of graphitization is very low. The optimum concentration range of dimethyl sulfide for carbon nanotube growth is 3.36-5.48. A large number of branched carbon nanotubes are formed when the flow rate of dimethyl sulfide is high. These branched carbon nanotubes have long branching and have great application potential in the field of nanodevices. However, when the flow rate of dimethyl sulfide is small, the products are less. The growth mechanism of branched carbon nanotubes was also studied and a simple growth model was proposed. 2. Carbon nanotubes (CNTs) and Y-shaped carbon nanotubes (CNTs) were prepared by chemical vapor deposition (CVD). The diameter of carbon nanotubes (CNTs) was distributed in the range of 30~70nm. The outer diameters of Y-shaped CNTs and the inner diameters of Y-shaped CNTs were about 607nmand 304nmrespectively. The morphology and structure of the products were characterized by SEM,TEM,Raman,XRD. The results showed that the graphitization degree of the carbon nanotubes was high and the purity of the products was also high. The electrical conductivity of three branches of a single Y-shaped carbon nanotube is tested. The results show that the Y-shaped carbon nanotube has a similar electrical conductivity to that of gold. 3. Carbon nanotubes filled with Co_9S_8 nanowires were prepared. The key factor affecting Co_9S_8 nanowires filling carbon nanotubes was the concentration of dimethyl sulfide, which not only provided carbon source, It also provides an essential sulfur source for Co_9S_8 filled carbon nanotubes. The optimum concentration range of Co_9S_8 nanowire filled carbon nanotubes is 1.26-1.47. When the concentration of dimethyl sulfide is higher than 1.47, Y-shaped carbon nanotubes are formed in the product. When the concentration of dimethyl sulfide is lower than 1.26, the product is hollow short carbon nanotubes. The growth mechanism of Co_9S_8 nanowires filled carbon nanotubes is "catalyst in-situ transformation induces carbon nanotubes filling".
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.1
本文编号：2364266
[Abstract]:Carbon nanotubes (CNTs) have attracted wide attention due to their unique physical and chemical properties and potential application value. In this paper, the method of preparing carbon nanotubes by chemical vapor deposition with dimethyl sulfide as carbon source and Co/MgO as catalyst was studied, and the effects of various experimental parameters, such as reaction temperature and gas flow rate, on the growth process of carbon nanotubes were investigated. The nucleation and growth mechanism of branched carbon nanotubes (CNTs) were studied systematically, and the controllable preparation of branched CNTs was realized. The effect of the concentration of dimethyl sulfide on the morphology and structure of carbon nanotubes filled with Co_9S_8 nanowires and the filling mechanism were studied. Preparation of Co_9S_8 nanowires filled with carbon nanotubes with good controllability. The main results are as follows: 1. Carbon nanotubes (CNTs) were prepared by catalytic pyrolysis of dimethyl sulfide. The results showed that the product was sensitive to temperature and the appropriate reaction temperature was 1000 掳C by comparison. The concentration and flow rate of dimethyl sulfide vapor also have a great influence on the yield and morphology of the product. When the concentration of dimethyl sulfide is very high, a large number of carbon atoms cover the surface of the catalyst, which results in the decrease of catalyst activity. The products are short carbon nanotubes or carbon nanofibers, and their graphitization degree is very low, but when the concentration of dimethyl sulfide is lower, the products are less and the degree of graphitization is very low. The optimum concentration range of dimethyl sulfide for carbon nanotube growth is 3.36-5.48. A large number of branched carbon nanotubes are formed when the flow rate of dimethyl sulfide is high. These branched carbon nanotubes have long branching and have great application potential in the field of nanodevices. However, when the flow rate of dimethyl sulfide is small, the products are less. The growth mechanism of branched carbon nanotubes was also studied and a simple growth model was proposed. 2. Carbon nanotubes (CNTs) and Y-shaped carbon nanotubes (CNTs) were prepared by chemical vapor deposition (CVD). The diameter of carbon nanotubes (CNTs) was distributed in the range of 30~70nm. The outer diameters of Y-shaped CNTs and the inner diameters of Y-shaped CNTs were about 607nmand 304nmrespectively. The morphology and structure of the products were characterized by SEM,TEM,Raman,XRD. The results showed that the graphitization degree of the carbon nanotubes was high and the purity of the products was also high. The electrical conductivity of three branches of a single Y-shaped carbon nanotube is tested. The results show that the Y-shaped carbon nanotube has a similar electrical conductivity to that of gold. 3. Carbon nanotubes filled with Co_9S_8 nanowires were prepared. The key factor affecting Co_9S_8 nanowires filling carbon nanotubes was the concentration of dimethyl sulfide, which not only provided carbon source, It also provides an essential sulfur source for Co_9S_8 filled carbon nanotubes. The optimum concentration range of Co_9S_8 nanowire filled carbon nanotubes is 1.26-1.47. When the concentration of dimethyl sulfide is higher than 1.47, Y-shaped carbon nanotubes are formed in the product. When the concentration of dimethyl sulfide is lower than 1.26, the product is hollow short carbon nanotubes. The growth mechanism of Co_9S_8 nanowires filled carbon nanotubes is "catalyst in-situ transformation induces carbon nanotubes filling".
【学位授予单位】：太原理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TB383.1
【参考文献】
相关期刊论文 前2条
1 张继红，魏秉庆，梁吉，高志栋，吴德海;激光熔覆巴基管／球墨铸铁的研究[J];金属学报;1996年09期
2 高永刚,施兴华,赵亚溥;碳纳米管的力学行为[J];机械强度;2001年04期
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