共查询到19条相似文献,搜索用时 156 毫秒
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回顾了C60、碳纳米管和石墨烯3种重要碳纳米结构的发现过程,着重总结了新型碳单质发现过程中对科学研究者有益的启示与思考。 相似文献
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针对催化化学气相法合成的碳纳米管含有金属、金属氧化物和碳杂质, 且缺陷较多进行了非破坏性纯化研究. 基于碳纳米管与碳杂质间结构、性质的微小差异, 1800 ℃使粗制的碳纳米管高温退火3 h, 为避免碳纳米管氧化, 高温退火过程在氩气气氛中完成. 运用扫描电镜、透射电镜观察碳纳米管的形貌和结构, 发现高温退火后, 碳纳米管的端帽大部分被打开. 能谱检测显示, 粗制的碳纳米管中的杂质(Al, Si, Ni, Cu 质量分数w分别为4.67%, 0.27%, 40.12%和1.34%)退火后被除去. 拉曼分析表明, 退火前后石墨D, G峰面积SD, SG分别从1314900降至474921, 767157降至566292, 退火不仅有效地去除了样品中的碳杂质, 而且使碳纳米管的缺陷得到一定程度的修复, 石墨化度随之大大提高. 研究提出了一种简单的、非破坏性的、便于规模化的纯化方法. 相似文献
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通过对碳单质概念发展历程的考证可知,碳是古代已知的非金属元素。至17—18世纪,随着科学实验的兴起和元素观的发展,金刚石和石墨均被证明为碳的单质,碳单质概念初步形成;20世纪80年代C60的发现及之后碳纳米管、石墨烯和T-碳的发现使人们对碳单质概念有了新认识。在化学教育中,须让学生认识到碳单质概念的发展史是物质的发现史,也是科学思想的演进史和科学方法的发展史。 相似文献
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在碳60(C60)[1]和碳纳米管(CNTs)[2]发现之前,人们知道碳通常显示石墨和金刚石两种晶体结构.自从C60和碳纳米管发现后,由于其独特的纳米结构而具有广泛的应用前景,国内外许多学者致力于研究它们的物理和化学特性,而C60、巴基葱(多层碳纳米球)、碳纳米管和金刚石之间的转变是所研究的焦点之一.目前,由碳的其他形式向金刚石转变的主要方法有:Meilunas等人[3]以C60和C70薄膜为基底气相生长多晶金刚石,C60和C70的稳定性和微平面结构在外界条件下,有利于金刚石成核和外延生长;Banhart[4]小组研究了在电子束辐射作用下巴基葱转变… 相似文献
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富勒烯和碳纳米管稳定性与形成机理的图形理论定性研究 总被引:2,自引:0,他引:2
应用图形理论对不同种类碳簇体系的Kekulé结构数进行了计算, 并在半经验方法(AM1)和密度泛函理论(DFT)水平上,讨论了不同种类碳簇的结构与稳定性. 基于Kekulé结构计数, C-Cσ键数, 富勒烯的表面曲率和能量, 对石墨碎片的卷曲行为以及富勒烯的形成机理进行了讨论. 研究结果表明石墨碎片的卷曲, 一端闭合, 到完全封闭, 可以减少结构中的悬键; 随着新的C-Cσ键生成, Kekulé结构数将急剧地增加, 特别是大的富勒烯和碳纳米管, 这种增加更为显著. 大量Kekulé结构间的共振使体系获得显著的共振稳定化能, 稳定具有张力的富勒烯和碳纳米管, 并驱动平面碳簇结构向闭合结构的转化. 对于Kekulé结构数相近的碳笼, 表面曲率对曲面结构的稳定性有重要的影响. 把Kekulé结构计数和表面曲率结合起来, 可以合理地理解球形笼状富勒烯、闭合纳米管和类“洋葱”型结构等高碳簇在热力学上的稳定性. 相似文献
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Juárez BH Meyns M Chanaewa A Cai Y Klinke C Weller H 《Journal of the American Chemical Society》2008,130(46):15282-15284
Insights to the mechanism of CdSe nanoparticle attachment to carbon nanotubes following the hot injection method are discussed. It was observed that the presence of water improves the nanotube coverage while Cl containing media are responsible for the shape transformation of the nanoparticles and further attachment to the carbon lattice. The experiments also show that the mechanism taking place involves the right balance of several factors, namely, low passivated nanoparticle surface, particles with well-defined crystallographic facets, and interaction with an organics-free sp2 carbon lattice. Furthermore, this procedure can be extended to cover graphene by quantum dots. 相似文献
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巴基管嵌锂电极性能的研究 总被引:12,自引:0,他引:12
用化学气相沉积法制备的巴基管作为锂离子电池的负极活性物质可以达到700mAh/g的容量,远超过了石墨嵌锂化合物理论容量。CVD巴基管电极经20次充放电循环后,放电容量保持率为65.3%,尽管CVD巴基管电极初次充放电效率低,但经表面镀铜修饰后,初次充放电效率可提高到55.9%。 相似文献
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A. V. Okotrub N. F. Yudanov V. M. Aleksashin L. G. Bulusheva O. A. Komarova U. O. Kostas P. N. Gevko N. V. Antyufeeva S. I. Il’chenko G. M. Gunyaev 《Polymer Science Series A》2007,49(6):702-707
Multi-walled carbon nanotubes synthesized by means of arc evaporation of graphite were used to prepare composites with a heat-resistant binder based on cyanoether. To increase the homogeneity of distribution of nanotubes in the polymer matrix, the carbon material was cleaned of graphite particles and amorphous carbon with a potassium permanganate solution in concentrated sulfuric acid. By means of X-ray photoelectron spectroscopy, it was shown that the proposed purification procedure leads to the grafting of oxygen-containing groups to the surface of carbon nanotubes. By means of differential scanning calorimetry, it was revealed that the oxide overcoat on the nanotube surface exerts an influence on the character of binder polymerization. The mechanical properties of a carbon-reinforced plastic with different nanotubes contents were measured. It was shown that the admixture of 0.25–0.50% carbon nanotubes improves the mechanical characteristics of carbon-reinforced plastics by 10–20%. 相似文献
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Jonathan N. Coleman Diarmuid F. O’Brien Brendan McCarthy Robert C. Barklie Werner J. Blau 《Monatshefte für Chemie / Chemical Monthly》2001,105(3):53-61
A novel experimental technique for the separation of nanotubes from other unwanted carbon species in arc generated carbon soot is described. A conjugated polymer was used to bind to nanotubes in solution. The resultant hybrid was soluble, whereas extraneous carbon material formed a sediment at the bottom of the sample bottle. The process was monitored using electron paramagnetic resonance (EPR) spectroscopy showing that 63% of nanotubes were kept in solution and 98.1% of impurities were rejected. This non-destructive purification allowed the calculation of the nanotube content in the carbon soot using EPR and thermogravimetric analysis (TGA). The measurement of nanotube content gave a purity value of 34% for the soot used in this study; this is compatible with estimates from electron microscopic determinations. 相似文献
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将聚甲基丙烯酸甲酯材料在多壁碳纳米管表面原位聚合, 利用这种修饰的碳纳米管作为基质辅助激光解析离子化(MALDI)的基质, 利用修饰后的碳纳米管可以“溶解”的特性实现了稳定的MALDI离子化, 并且消除了在低质量端的基质噪音. 此类聚合物衍生的碳纳米管具有相对较好的亲水性表面, 可“溶解”在溶剂中. 此方法适用于有机小分子、多肽、聚合物和蛋白质酶解肽段的质谱分析. 实验表明聚甲基丙烯酸甲酯固定化碳纳米管能有效地吸收和传递激光能量, 可与样品充分地分散混合, 质谱检测背景低, 重现性好, 具有较宽的可测质量范围. 此方法在小分子快速检测和蛋白质组学方面有很大的应用前景. 相似文献
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The fabrication, evaluation and attractive performance of multiwall carbon nanotube(MWCNT)/polysulfone biocomposite membrane modified thick-film screen-printed electrochemical biosensors are reported. The fabricated carbon nanotube/polysulfone (CNT/PS) strips combine the attractive advantages of carbon nanotube materials, polysulfone matrix and disposable screen-printed electrodes. Such thick-film carbon nanotubes/polysulfone sensors have a well defined performance, are mechanically stable, and exhibit high electrochemical activity. Furthermore, biocompatibility of CNT/PS composite allows easy incorporation of biological functional moiety of horseradish peroxidase by phase inversion technique. The comparison of graphite with MWCNT as conductor material is described in this paper. The proposed H(2)O(2) biosensor exhibited a linear range (applied potential, -0.2 V) from 0.02 to 0.5 mM and a K(M)(app) of 0.71 mM. 相似文献
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Agnihotri S Mota JP Rostam-Abadi M Rood MJ 《Langmuir : the ACS journal of surfaces and colloids》2005,21(3):896-904
A procedure, combining molecular simulation, Raman spectroscopy, and standard nitrogen adsorption, is developed for structural characterization of single-walled carbon nanotube (SWNT) samples. Grand canonical Monte Carlo simulations of nitrogen adsorption are performed on the external and internal adsorption sites of homogeneous arrays of SWNTs of diameters previously determined by Raman spectroscopy of the sample. The results show the importance of the peripheral grooves of a nanotube bundle at low relative pressure and the insensitivity of nanotube diameter toward adsorption on the external surface of the bundle at higher pressures. Simulations also reveal that samples containing thin nanotubes have less internal adsorption capacity that saturates at lower pressure than those comprising large diameter nanotubes. The fraction of open-ended nanotubes in a sample can be estimated by scaling the simulated internal adsorption inside nanotubes to obtain a near perfect fit between simulated and experimental isotherms. This procedure allows extrapolation of adsorption properties to conditions in which all nanotubes in the sample are open-ended. 相似文献
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Jonathan N. Coleman Diarmuid F. O’Brien Brendan McCarthy Robert C. Barklie Werner J. Blau 《Monatshefte für Chemie / Chemical Monthly》2001,132(1):53-61
Summary. A novel experimental technique for the separation of nanotubes from other unwanted carbon species in arc generated carbon
soot is described. A conjugated polymer was used to bind to nanotubes in solution. The resultant hybrid was soluble, whereas
extraneous carbon material formed a sediment at the bottom of the sample bottle. The process was monitored using electron
paramagnetic resonance (EPR) spectroscopy showing that 63% of nanotubes were kept in solution and 98.1% of impurities were
rejected. This non-destructive purification allowed the calculation of the nanotube content in the carbon soot using EPR and
thermogravimetric analysis (TGA). The measurement of nanotube content gave a purity value of 34% for the soot used in this
study; this is compatible with estimates from electron microscopic determinations.
Received June 23, 2000. Accepted July 3, 2000 相似文献