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乙醇催化燃烧法可以方便的制备出碳纳米管和碳纳米纤维。介绍采用该方法制备出一种独特的竹节形的碳纳米管,利用乙醇作为碳源和燃料,提供材料生长所需的能量;利用Cu薄片作为基底;利用FeCl3或Fe(NO3)3作为催化剂先体。通过扫描电子显微镜(SEM),透射电子显微镜(TEM),对黑色絮状的沉积产物进行表征。实验结果表明,产物中的碳纳米管具有较好的竹节形结构。实验也表明制备的竹节形碳纳米管的形貌和微结构与其独特的制备条件有关,如:火焰的抖动,催化剂先体溶液的浓度,制备时间等。并对竹节形碳纳米管的形貌和生长机制进行了详细的讨论。 相似文献
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采用催化化学气相沉积法将由C包覆的纳米铁颗粒(FeNP)原位沉积于碳纳米管(CNTs)表面并形成不同形貌的碳纳米管/纳米铁颗粒(CNTs/FeNP)杂化结构。使用扫描电子显微镜、透射电子显微镜对制备的杂化结构进行微观形貌分析和结构表征。结果显示,纳米铁颗粒通过石墨片层结构与碳纳米管相连,具有良好的界面结合。当噻吩的添加量较低时,产物中碳纳米管的直径减小,产量增多。当噻吩的添加量超过0.5%时,可以得到CNTs/FeNP杂化结构。使用X射线能谱仪、X射线衍射仪分析了杂化结构的成分及其相对含量,结果显示体系中的Fe主要以α-Fe、γ-Fe和Fe3C的形式存在,并且Fe的含量随噻吩含量的增加不断增加。通过研究纳米铁颗粒的形成及其在碳纳米管表面的沉积,揭示了CNTs/FeNP杂化结构的形成机理。 相似文献
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本文建立了碳纳米管的结构模型,用平面波赝势方法,采用广义梯度近似的密度泛函理论,对扶椅型碳纳米管(5,5),(7,7)和(9,9)的能带结构和电子密度分布进行了计算,其能带间隙分别为0.024,0.142和0.147。计算结果表明碳纳米管(5,5)(7,7)(9,9)均为导体,在费米能级的电子密度均不为0,体现出金属性质。从电子结构上可以看出碳纳米管的电子分布在s亚层和p亚层上,由于碳纳米管弯曲,会形成不同形式的sp杂交轨道,但任何形式的碳纳米管在费米能级处的电子主要分布在p轨道。 相似文献
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概括了碳纳米管(CNTs)作为一维纳米结构构筑模板的优势,重点评述了在以CNTs为模板制备CdS@CNTs核壳异质结构纳米线方面的研究进展,通过代表性的研究工作介绍了以CNTs为模板制备多种CNTs/无机半导体核壳异质结构纳米线的新成果,并对相关研究领域目前存在的关键问题进行了归纳与点评。 相似文献
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本文用XRD,TEM分析了热压自生α/β-Sialon复相陶瓷的组织结构,结果表明长柱状β-Sialon晶粒与等轴状α-Sialon晶粒相互结合在一起,α-Sialon相含量约为30Vol%,少量结晶相存在于三角晶界处。 相似文献
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A possible mechanism of the formation of fullerenes and carbon nanotubes is proposed that is based on the notion of the strongly
correlated state of π electrons in these materials (as well as in graphene layers). The presence of this state, in which the
π electron densities on both sides of the carbon framework tend to be equal, decreases the energy of the system and stabilizes
the carbon structure modifications under consideration. It is suggested that the graphene layer fragments considered as the
initial material are polarized under the action of positive ions of inert gases or transition metals. This polarization leads
to a redistribution of π electrons between the two sides of the initially planar graphene layer, which violates the equality
of electron densities. As a result, the layer exhibits bending, which leads to the restoration of this equality. Under conditions
of the strongly correlated π electron state, polarization not only modifies the state of hybridization of the polarized carbon
atoms, but also leads to the formation of localized singlet pairs of π electrons (localized π-bonds). These changes maintain
and additionally stabilize the curved structure upon termination of the polarizing action. 相似文献
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Apatite coating on carbon nanotubes (CNTs) was done with a biomimetic coating method. The multi-walled CNTs (MWNTs) of curled shape with about 30 nm in diameter were immersed for 2 weeks in the simulated body fluid. Observation by scanning electron microscopy (SEM) showed the formation of apatite on the MWNTs surface. The clusters of spherules consisting of needle-shaped apatite crystallites were massively grown on the aggregated MWNTs. The crystallites of 100 nm in width and 200–500 nm in length were grown perpendicularly to the longitudinal direction and radially originating from a common center of a single MWNT. Thus, the architecture of crystalline apatite at nano-scale levels could be produced by simple method and the MWNT may be acting as core for initial crystallization of apatite. 相似文献
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定向/有序碳纳米管的制备及生长机理的研究进展 总被引:1,自引:0,他引:1
综述了国内外有序、定向碳纳米管(CNTs)制备的研究进展,着重介绍了模板法在定向碳纳米管制备方面的应用,简要介绍了制备定向碳纳米管的一些其它方法。对定向碳纳米管的生长机理进行了阐述。并简要说明了现阶段国内外研究存在的问题以及世界范围内对碳纳米管的研究前景。 相似文献
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魏芹芹 《功能材料与器件学报》2012,18(1):63-69
随着集成电路的不断发展,电路中互连线规模越来越大,尺寸越来越小,需要承受的电流密度越来越大.在这种趋势下,传统的铜互连线的有效性和可靠性都随之变差.由于碳纳米管具有良好的电学,热学和机械性能,使其成为目前研究较热的互连材料之一.本文概述了碳纳米管用于集成电路互连的优势,碳纳米管互连的电路模型,碳纳米管互连面临的挑战及其... 相似文献
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The formation of individual graphene foils (GF) has been evidenced in the present study inside multi-walled carbon nanotubes. The graphene foils are attached on one side to a catalyst nanoparticle and on the other side to the internal walls of the nanotube. Moreover, results suggest that a necking process occurs in which internal carbon walls are deformed until formation of the graphene foil. A possible mechanism for the GF formation is then proposed. 相似文献
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Jinling Song Shouai Feng Jianghong Zhao Zhenping Zhu 《Materials Research Bulletin》2010,45(9):1234-1239
Activated carbon (AC), a common carbon material, is employed as catalyst to synthesize carbon nanotubes (CNTs) through chemical vapor deposition (CVD) and detonation-assisted CVD methods. The results show AC can effectively catalyze CNT formation. From the microscopic observations on morphologies and structures of the formed intermediates, it is found that carbon-catalyzed CNT formation follows particle-wire-tube stepwise evolution mechanism, in which carbon nanoparticles first assemble into wire-like nanostructures, then evolve into nanotubes via particle-particle coalescence and structural crystallization. 相似文献
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碳纳米管在超级电容器中的应用研究进展 总被引:6,自引:4,他引:6
超级电容器是近年来发展起来的一种新型储能装置。碳纳米管由于具有独特的中空结构,良好的导电性和高的比表面积,被认为是超级电容器理想的电极材料之一,引起了广泛的关注。通过介绍碳纳米管在超级电容器中的应用研究进展,评述了碳纳米管、活化碳纳米管、碳纳米管/金属氧化物复合物以及碳纳米管/导电聚合物复合物用做超级电容器电极材料的特点和性能。认为单纯的碳纳米管由于比表面积小,比容量偏低。化学活化可以显著提高碳纳米管的比表面积,增大其比电容。将碳纳米管与准电容材料金属氧化物或导电聚合物复合。可以发挥各自的优势,从而得到低成本、高性能的复合电极材料,将是今后发展的一个方向。 相似文献
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The mass transportation mechanism in electric-biased carbon nanotubes (CNTs) is investigated experimentally. Except for the widely accepted electromigration mechanism, we find out the thermal effect can also induce the mass transportation in the form of thermomigration or thermal evaporation. Moreover, the convincing in situ transmission electron microscope experiment results show the thermal gradient force overrides the electromigration force in most conditions, according to specific parameters of the CNTs and "cargos". A full analysis on the thermal gradient force and electromigration force imposed on the cargos is given, thus our experimental results are well explained and understood. 相似文献