固相合成碳纳米管的方法及性能测试

发布时间：2018-02-06 01:58

  本文关键词： 固相合成 掺氮碳纳米管 氢氧化钾活化 二氧化碳吸附　出处：《宁波大学》2015年硕士论文　论文类型：学位论文

【摘要】：碳纳米管因其独特的管状结构和物理化学性质,一直是功能材料领域的研究热点。碳纳米管的合成方法主要有石墨电弧法、激光蒸发法以及化学气相沉积(CVD)法。目前,CVD法已经实现商业化碳纳米管的大规模生产。但其存在产物粉尘化等不可避免的问题,严重阻碍了碳纳米管的大规模应用。本文介绍了一种新颖的固相合成碳纳米管的方法。通过该方法可以得到具有一定宏观形状和尺寸的碳纳米管,可以很好的解决CVD法所带来的粉尘化问题,而且合成步骤更加简单,设备要求低,并可以实现氮元素的直接掺杂。具体合成流程为:以二乙烯苯为碳源,加入一种咪唑类离子液体和铁氰化钾,在一定条件下共聚形成一种含氮金属有机聚合物作为生长碳纳米管的前驱体。之后在持续氮气流的保护下,将前驱体置于管式炉中经过高温热解生长具有一定宏观尺寸和形状的掺氮碳纳米管。采用扫描、透射电子显微镜以及拉曼光谱等多种手段对产物进行了表征,分析不同碳化温度条件下生长碳纳米管的纯度及结构差异,确定800℃为该前驱体生长碳纳米管的最佳温度。为了进一步研究固相合成碳纳米管在二氧化碳吸附领域的潜在应用,对其进行了KOH活化处理以增大其比表面和改善孔结构。结果表明,随着活化温度的升高,碳纳米管的比表面积逐渐增加,但同时氮元素的流失也随之更加严重。当活化条件为700℃保温2 h时,碳管比表面积大小由315 m2/g增大到544 m2/g,增加70%以上,微孔孔容增加超过一倍,氮含量损失低于50%。常温常压下二氧化碳吸附测试结果显示,掺氮碳纳米管比表面积大小是其二氧化碳吸附能力的重要影响因素,比表面积相差很大时,比表面积大的吸附能力强。进一步深入分析表明,单位微孔孔容的CO2吸附量(y)对表面氮含量(x)存在线性依赖关系::y=5.00+4.25x,这为高容量CO2吸附材料的结构优化提供了新思路。
[Abstract]:Carbon nanotubes (CNTs) have been the focus of research in the field of functional materials because of their unique tubular structure and physical and chemical properties. The main synthesis methods of CNTs are graphite arc method. Laser evaporation and Chemical Vapor deposition (CVD) methods have been widely used to produce commercial carbon nanotubes (CNTs). However, there are some inevitable problems such as product dusting and so on. In this paper, a novel method of solid phase synthesis of carbon nanotubes is introduced, by which carbon nanotubes with certain macroscopic shape and size can be obtained. It can solve the dust problem caused by CVD method, and the synthesis steps are simpler, the equipment requirements are low, and the direct doping of nitrogen elements can be realized. The specific process is: diethylbenzene as carbon source. A kind of imidazole ionic liquid and potassium ferricyanide were added to form a nitrogen-containing metal-organic polymer as the precursor of carbon nanotube growth under certain conditions, and then under the protection of continuous nitrogen flow. Nitrogen-doped carbon nanotubes (NCNTs) were grown by pyrolysis at high temperature in a tube furnace. The products were characterized by scanning, transmission electron microscopy and Raman spectroscopy. The purity and structure of carbon nanotubes grown at different carbonization temperatures were analyzed. In order to further study the potential application of carbon nanotubes in carbon dioxide adsorption field, 800 鈩，

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