Nanographite structures formed during annealing of disordered carbon containing finely-dispersed carbon nanocapsules with iron carbide cores
Nanographite structures formed during annealing of disordered carbon containing finely-dispersed carbon nanocapsules with iron carbide cores
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DOI：
10.1016/j.carbon.2008.12.029
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发表时间：
2009-04
期刊：
影响因子：
10.9
通讯作者：
R. Sergiienko;E. Shibata;Sung Hoon Kim;Takuya Kinota;Takashi Nakamura
中科院分区：
文献类型：
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作者：
R. Sergiienko;E. Shibata;Sung Hoon Kim;Takuya Kinota;Takashi Nakamura
采用超声辐照乙醇溶液，通过小电流等离子体放电制备了以碳化铁为核心的碳纳米管。研究了含碳纳米管的无序碳在900°C退火2 h后的纳米石墨结构。透射电子显微镜（TEM）研究表明，退火后的粉末样品中大部分无序碳转变为纳米石墨带、空心多面体石墨笼和厚碳壳，碳层具有乱层结构。碳层的TEM观察显示堆叠缺陷。数字化图像的选区衍射和快速傅里叶变换显示，碳层间距从3.4到3.5纳米不等。XRD分析表明，粉末样品在900°C退火2 h后，发生了碳化铁核的分解，并在2θ = 25.9°（d 002 = 3.44 θ）处检测到一个轮廓分明的宽碳峰（002）。ID/IG比的增长和D峰向较低波数的偏移可以指示石墨簇的尺寸增加和有序碳结构，即纳米石墨结构的出现。
Disordered carbon containing finely-dispersed carbon nanocapsules with iron carbide cores were synthesized by a modified method in which low-current plasma discharge was generated in liquid ethanol with ultrasonic irradiation. The structure of nanographite forms prepared by the annealing at 900°C for 2h of disordered carbon containing finely-dispersed carbon nanocapsules was studied. Transmission electron microscopy (TEM) studies of the powder sample after annealing revealed most part of disordered carbon was transformed into nanographite ribbons, hollow polyhedral graphitic cages and thick carbon shells with the turbostratic structure of carbon layers. TEM observations of the carbon layers revealed stacking defects. Selected-area diffraction and fast Fourier transforms of digitized images revealed that carbon inter-layer spacings vary from 3.4 to 3.5Å. XRD analysis showed that annealing of the powder sample at 900°C for 2h resulted in the decompositions of iron carbide cores and a well-defined broad carbon peak (002) centered at 2θ≈25.9° (d002=3.44Å) was detected. The growth of the ID/IGratio and shift of the D peak to a lower wavenumber may indicate increase in size the graphite clusters and ordering carbon structure, i.e. appearance of nanographite structures.