以甲烷和氧气为前驱体,二茂铁为催化剂,采用气相爆轰法在密闭反应管中合成多壁碳纳米管。运用X射线衍射(XRD)、透射电子显微镜、Raman光谱等手段对多壁碳纳米管进行形貌表征和物相、成分分析。结果表明:所制备的多壁碳纳米管呈弯曲缠绕状,管径分布在20~50nm,长度达数微米,具有优异的管状结构,并且石墨化程度较高;碳纳米管中除含碳元素外,还包含少量纳米铁颗粒,且产物中含有少量碳化铁。XRD分析表明,爆轰反应发生后催化剂被分解、还原为金属单质。根据实验结果和理论分析,提出了气相爆轰法合成碳纳米管的机理。
Multi-walled carbon nanotubes (MWCNTs) were synthesized via the detonation of methane and oxygen as precursors and ferrocene as catalyst in a sealed stainless steel pressure vessel. Then the MWCNTs were characterized by X-ray diffraction (XRD), transmission electron microscopy and Raman spectroscopy. The results indicate that MWCNTs present appearance of entangled morpholo- gies with outer diameters of 20-50 nm and lengths up to several microns, which have an excellent tubular structure and a relatively high graphitization degree;A small number of iron (Fe) nanoparti- cles remaining in the MWCNTs consist of Fe3C, which results from the continuous supply of carbon source and iron catalyst. XRD analysis shows that, after the detonation reaction,the catalyst is broken down and reduced to metal simple substance. Through the experimental results and theoretical analy- sis,we propose the formation mechanism of gas detonation synthesis of carbon nanotubes.