【作者】 陈刚；

【导师】 邱介山；

【作者基本信息】 大连理工大学 ， 化学工艺， 2007， 博士

【摘要】 双壁纳米碳管是由两层石墨烯片卷曲形成的无缝中空纳米管，其结构介于单壁和多壁纳米碳管之间，因此它兼具单壁和多壁纳米碳管较多的性能。双壁纳米碳管的制备是研究其特殊性能与应用的必要基础条件。本文研究了直流电弧法制备双壁纳米碳管的工艺过程和双壁纳米碳管的化学纯化方法，用透射电子显微镜（TEM）、热重分析仪（TG）和拉曼光谱仪（Raman spectrum）等对双壁纳米碳管进行了结构表征和纯度分析；同时对双壁纳米碳管在加氢催化、直接甲醇燃料电池及纳米复合材料领域的应用进行了探索。具体内容包括以下几个方面：（1）以廉价的无烟煤为碳源，通过干混法添加催化剂制成了煤基炭棒，以这种炭棒为直流电弧炉阳极，考察了不同催化剂和气氛条件对制备双壁纳米碳管的影响，研究结果表明单质铁催化剂和含氢气氛有利于制备高质量的双壁纳米碳管。利用液相浸渍法制备了催化剂尺寸较小的煤基炭棒，研究了以这种炭棒为阳极，氢气、氩气及它们的混合气氛对电弧放电制备双壁纳米碳管的影响，结果说明：在Ar和H₂(300 Torr，V_Ar：V_H2=2：1)的混合气氛中，得到的双壁纳米碳管具有相对较高的纯度和产量；以铁为催化剂的产量比钴或镍的高。用富勒烯残余烟灰为原料，分别使用干混法和液相浸渍法制备了富勒烯烟灰基炭棒，并以这两种富勒烯烟灰基炭棒为阳极，在Ar和H₂(300 Torr，V_Ar：V_H2=2：1)的混合气氛中，制备得到高质量的双壁纳米碳管。（2）用化学纯化法对双壁纳米碳管粗产品进行纯化，得到了纯度较高的双壁纳米碳管。发现用浓硫酸和浓硝酸的混和溶液可有效去除以煤为原料制得的双壁纳米碳管中的金属杂质，通过进一步的空气氧化可以获得纯度超过90wt.％的双壁纳米碳管。经过两次的空气氧化与浓盐酸的处理过程，以富勒烯残余烟灰为原料制得的双壁纳米碳管中大量的金属和绝大部分炭杂质被除去，最终可获得纯度超过80wt.％的双壁纳米碳管。在纯化过程中，随着双壁纳米碳管纯度的增加，产品的比表面积和中孔孔容均有较大的提高。（3）硝基氯苯催化加氢反应结果表明，双壁纳米碳管内的铁、钴或镍颗粒具有一定的加氢活性，可作为磁性分离催化剂使用。以双壁纳米碳管为载体浸渍担载钌后，加氢催化性能得到了较大的提高，且随着担载量的增加和反应温度的升高而提高。研究了纯双壁纳米碳管和其他炭材料浸渍担载钌催化剂时的差别，并分别考察了它们的催化加氢活性，结果表明：纯双壁纳米碳管表面缺乏更多的担载位时，钌颗粒容易发生聚集和长大，因此未表现出较好的活性。以担载铂钌双金属颗粒的纯双壁纳米碳管为直接甲醇燃料电池的阳极催化剂，循环伏安曲线和单电池性能的测试结果表明，双壁纳米碳管是一种性能优异的直接甲醇燃料电池阳极催化剂载体。通过向双壁纳米碳管内填充AgCl纳米线，制备了大量双壁纳米碳管与AgCl的纳米复合材料，拉曼表征结果表明AgCl纳米线与双壁纳米碳管的内管间存在着电子转移。（4）除双壁纳米碳管外，本文还研究了其他新型炭材料的电弧制备工艺，发现采用不同的工艺条件可以分别获得单壁纳米碳管、填充碳管或Y-型碳管。更多还原

【Abstract】 Double-walled carbon nanotubes （DWCNTs） have many advantages over single-walledcarbon nanotubes （SWCNTs） and multi-walled carbon nanotubes （MWCNTs）. To study theproperties and application of DWCNTs deeply and thoroughly, controllable synthesis ofDWCNTs must be addressed. In this thesis, the fabrication of DWCNTs by arc-discharge isstudied, and the potential applications in the field of hydrogenation, direct methanol fuel celland nanocomposites have been explored.One Chinese anthracite coal is used as carbon source that was mixed with catalystpowder and coal tar directly to prepare electrode rods. Synthesis of DWCNTs fromcoal-derived anodes with iron, alloy and ferreous salts as catalyst is studied in differentatmosphere. The results indicate that iron catalysts and hydrogen atmosphere are importantfactors for the production of DWCNTs.The coal-derived anode with iron nanoparticles can be prepared by liquid impregnationmethod. The effects of atmosphere on fabrication of DWCNTs are studied. The results showthat high quality DWCNTs can be obtained in large scale when the mixture of argon andhydrogen (300 Torr, V_Ar:V_H2=2:1) is used in the process. The yield of DWCNTs fromcoal-derived anode using iron as catalyst is higher than that using cobalt or nickel as catalyst.Fullerene waste soot （FWS） was used to make anodes with Fe₂（SO₄）₃ and FeCl₂ ascatalyst precursor, and the anodes were used to produce DWCNTs. In the mixture of argonand hydrogen (300 Torr, V_Ar:V_H2=2:1), high quality DWCNTs can be fabricated in large scalefrom these FWS-derived anodes.The as-synthesized DWCNTs from coal were purified with a mixture of concentratedsulfuric and nitric acids （3:1, 98wt.% and 70wt.%, respectively） which removes most ironparticles in high efficiency. After oxidation by air and being washed with HCl solution, thepurity of DWCNTs can reach ca.90wt.%.Most impurity in the as-synthesized DWCNTs from FWS can be removed by two stepspurification of being oxidized by air and washed with HCl acid. After purification process, thepurity of DWCNTs can reach ca.80wt.%.Raw DWCNTs from coal with iron, nickel or cobalt as catalyst show activity ofhydrogenation o-chloronitrobenzene （o-CNB）. Meanwhile, the magnetic property of metalnanoparticles encapsulated with carbon shell in the raw DWCNTs is favorable for isolating the catalyst from reaction system. The conversion will increase evidently after the rawDWCNTs supported with Ru nanoparticles. As loading weight or reaction temperatureincrease, the conversion will be improved evidently.The properties of purified DWCNTs and other carbon materials supported with Runanoparticles behaving in hydrogenation o-CNB are researched. As a result, mostmonodisperse Ru particles on the purified DWCNTs is less than 3 nm, but conversion ofo-CNB is not high for the reason that there are still some large assemble particles in thecatalyst.Results of cyclic voltammetry and single cell performance indicate that high purityDWCNTs loading Pt and Ru may be a good anode catalyst for direct methanol fuel cells.The nanocomposites of DWCNTs filled with AgCl nanowires were synthesized bycapillarity in nitrogen atmosphere. Raman spectroscopy is used to characterize the product,and the Raman results indicate that in the filled sample the charge transfer occurs betweenAgCl nanowires and inner tube of DWCNT evidently.Furthermore, SWCNTs, carbon tubes filled with foreign material and Y-junction carbontubes synthesized by arc-discharge in suitable conditions are also studied in the paper.更多还原