金属性与半导体性碳纳米管的密度梯度分离法

【作者】 吴秀力；

【导师】 廉永福；

【作者基本信息】 黑龙江大学 ， 无机化学， 2011， 硕士

【摘要】 为分离金属性与半导体性单壁碳纳米管,本文以蔗糖为梯度介质对密度梯分离方法进行系统的研究。本文采用YNi2合金为催化剂使用电弧放电的方法制备单壁碳纳米管。分别采用硝酸回流法和表面活性剂提纯单壁碳纳米管,硝酸回流法主要经过超声、回流、水洗、研磨、焙烧。而用表面活性剂提纯单壁碳纳米管主要经过超声、回流、水洗、再超声、超速离心。分别用可见-近红外光谱、拉曼光谱、热重分析、扫描电镜进行表征,发现用硝酸和表面活性剂处理后都可以得到较纯净的单壁碳纳米管。而且对表面活性剂提纯单壁碳纳米管在离心力和离心时间等方面进行初步的讨论,优化实验条件,提高分离效率。实验结果表明,用表面活性剂不仅可以纯化单壁碳纳米管,而且其离心液可以用于密度梯度分离。本文分别从物理、化学和生物的角度介绍了目前分离金属性和半导体性单壁碳纳米管的方法,密度梯度分离碳纳米管的方法优于其它的方法,能够将不同导电性单壁碳纳米管分离出来,并且在分离的数量上优于所有其它的分离方法。并对密度梯度分离法的影响因素进行初步研究,采用可见-近红外光谱和拉曼光谱对分离的单壁碳纳米管进行了表征。在离心管不同层,获得金属性单壁碳纳米管的最高纯度为68.49%,而半导体性单壁碳纳米管最高纯度为96.47%。密度梯度分离法不仅可以按不同的导电性排列单壁碳纳米管,而且可以按直径大小排列单壁碳纳米管,并对其初步讨论。更多还原

【Abstract】 For the separation of metallic and semiconducting single-walled carbon nanotubes(SWCNTs), In this paper, the method of density gradient separation has been systematic investigated in gradient medium of sucrose .In this paper, the SWCNTs have been prepared with the catalyst of YNi2 alloy via arc discharge. We purify the SWCNTs with nitric acid reflux and surfactant, respectively, and the method of nitric acid reflux mainly involves the ultrasound, reflux, washing, grinding, roasting. The samples have been characterized by near infrared visible spectroscopy, Raman spectroscopy, thermal analysis, scanning electron microscopy and it is found that the higher pure SWCNTs can be obtained via nitrate and surfactant treatment. Furthermore the aspects of centrifugal force and centrifugation time have been initially discussed on purifying SWCNTs with surfactant, in order to optimize experimental conditions and increase the separation efficiency. The results show that the surfactant can not only purify SWCNTs, but also its solution of centrifugation can be used for separation of density gradient.To begin with we will provide a brief introduction on the current methods of the separation of metallic and semiconducting SWCNTs in the field of chemical, physics and biological. Also, the method of separation of carbon nanotubes(CNTs) with density gradient can be equipped to separate from SWCNTs of different electrical conductivity, both of the density gradient method and quantity of separation of CNTs are superior to the others. In addition, the influencing factors of method of density gradient separation and the samples of SWCNTs have been preliminary studied and characterized by visible- near infrared spectroscopy and Raman spectra, respectively. In different layers of solution in centrifuge tube, we have obtained metallic SWCNTs of the highest purity of 68.49% and semiconducting SWCNTs of the high purity up to 96.47%. The method of density gradient can not only be used to arrange SWCNTs by different electroconductibility, but also can be ordered to SWCNTs by the diameter, and allow be initially discussed.更多还原