【作者】 张凡；

【导师】 邱介山；

【作者基本信息】 大连理工大学 ， 有机化工， 2000， 硕士

【摘要】 以纳米管和纳米颗粒为代表的新型纳米碳材料具有独特的结构和特殊的物理化学性质，已在凝聚态物理、材料科学、化学以及纳米电子元器件等领域显示出广阔的应用前景，其高效制备方法的开发及应用途径的探索日益受到广泛的重视。目前，国际上针对碳纳米管的研究，主要集中在原料及制备工艺的改进、化学修饰及填充、结构及其缺陷、电输运特性、催化及储氢应用等方面。 本文选取了不同变质程度的若干种煤样，用两步炭化法制成焦棒，然后用电弧蒸发焦棒制备成以纳米管为主要产物的纳米碳材料。采用吡啶预处理空气氧化法和CO₂氧化法等方法对碳纳米管粗品进行纯化。以硝基苯加氢为探针反应，考察了纳米碳材料的催化加氢性能并与其它碳材料进行了对比。上述实验过程中不同阶段的产物分别用SEM、HRTEM、IR、GC和GC-MS等手段进行了表征。 实验结果表明： 1．由所选煤样均可制得碳纳米管为主要产物的纳米碳材料，其收率及结 构形态与煤样预处理工艺参数、电弧蒸发实验工艺参数及操作条件有 关。 2．煤种的结构、性质、组成不仅影响纳米碳材料的产率，还影响纳米碳 材料的形状。某些煤种因特殊的组成和性质使其纳米碳材料的产率超 过60％，高于传统的光谱纯石墨的水平。 3．吡啶预处理空气氧化法是提纯煤基碳纳米管的一种有效方法。 4．与以其它一些碳材料为载体的催化剂相比，以纳米碳材料为载体的催 化剂在硝基苯加氢反应中催化性能更为突出，这与其中的碳纳米管、 碳纳米颗粒特殊的结构和性质有关。更多还原

【Abstract】 In the past decade novel carbon nanomaterials including carbon nanotubes and carbon nanoparticles with unusual structures and outstanding physical and chemical properties have generated great interest in the whole world. This interest has been driven chiefly by the potential applications of this new class of carbon materials, which lie in areas as diverse as electronic devices, tools in nanotechnology, catalyst supports and hydrogen storage. To date, production methods for carbon nanotubes are well established and allow their synthesis on a scale of grams per day, but these preparation methods or processes are still needed to be optimized in terms of efficiency and targeted carbon materials. With this in mind different raw materials or precursors such as high purity graphite and hydrocarbons are tested aiming to further improve the yield and purity of carbon nanotubes and to find new forms of carbon nanomaterials. In this paper, some Chinese coals with different properties are evaluated using a conventional arc discharge equipment with an aim of finding a suitable one for preparing novel carbon nanomaterials such as those fullerene-like nanoparticles with only a few carbon layers. The coal samples are first pretreated and carbonized to make coke rods which are conductive and self-supporting. The obtained coke rods are vaporized via arc discharge to prepare carbon nanomaterials that form as the inner soft core in a deposit on the cathode. The obtained nanotubes materials are pretreated by pyridine and purified using air or CO2. Catalysts based on carbon nanomaterials are prepared and their catalytic performance are investigated with the hydrogenation of nitrobenzene as a probe reaction and compared with other carbonaceous supports. The techniques including SEM -~ HRTEM -. JR~ GC and GC-MS etc are used in this paper when it is appropriate and necessary to characterize the materials or to analyze the reaction products in the related ill experiments. The main results are as follows 1. Nanomaterials including nanotubes can be prepared from all the coal samples tested. The yield and morphologies of the carbon nanomaterials are related to the pretreatment conditions of the coal samples and preparation process parameters. 2. The properties, constitutions and structures of coal samples have influences on the yields of the carbon nanomaterials, and on their structures and abundance as well. In some cases the carbon nanomaterials yield obtained from some coal samples is higher than that from high purity graphite under the same experimental conditions, which leads one to infer that the high yield must be closely related to the intrinsic chemical structures of coal precursors. 3. The arc discharge method yields an inhomogeneous raw product, consisting of nanotubes and other carbon species such as fullerenes, polyhedra and other graphitized carbon structures. Hence, in order to exploit the enormous potential for technical application, effective purification of this material becomes necessary. It is found that the coal-derived raw carbon nanomaterials could be effectively purified via pyridine pretreatment followed更多还原