火柴棒状纳米碳管的制备及其生长机理

以钨酸钠为钨源,氯化钠为诱导剂,通过水热法制备了三氧化钨(WO3)纳米棒,再以葡萄糖为碳源,经再次水热反应对WO3表面进行碳包覆,然后在氢气和甲烷混合气氛中反应一段时间获得了具有火柴棒状结构的纳米碳管。采用X射线衍射分析、场发射扫描电子显微镜、透射电子显微镜和X射线能量散射谱等手段对样品的晶型、形貌、微结构和表面化学元素进行了表征与分析。结果表明,样品由纳米碳管和碳化钨(WC)构成。其中,纳米碳管为火柴棒状,长度0.5~1.0μm,直径100 nm左右;WC颗粒位于纳米碳管内部,其大小决定了火柴棒状纳米碳管的内径。这充分说明WC在碳管的生长过程中充当催化剂的作用。

Preparation of match-like carbon nanotube and its growth mechanism

Tungsten trioxide nanorod was prepared by a hydrothermal method using sodium tungstate as tungsten source and sodium chloride as an inducer. The nanorod was coated with carbon by a hydrothermal reaction once again and using glucose as a carbon source. Match-like carbon nanotube was fabricated by reaction under a mixed gas of H₂ and CH₄ with a volume ratio of H₂ to CH₄ of 1:4. The crystal phase, morphology, microstructure and chemical elements of the samples were characterized and analyzed by X-ray diffraction, scanning electron microscope, transmission electron microscope and X-ray energy dispersion spectrum. The results showed that the sample was consisted of carbon nanotube and tungsten carbide (WC). The morphology of the carbon nanotube was of match-like with a length between 0.5 μm and 1.0 μm, and a diameter around 100 nm. WC particles laid in the inner space of the carbon nanotube and the inner diameter of the nanotube was depended on the diameter of WC particle. These implied that WC particle took a catalytic role during the growth of the carbon nanotube.