Ni/MgO催化剂下碳纳米管的生长特性

采用射频等离子体增强化学气相沉积法(RF-PECVD),以Ni/MgO为催化剂,在Si基片上生长了碳纳米管,采用X射线衍射(XRD)、扫描电镜(SEM)、Raman光谱以及高分辨透射电镜(HRTEM)等对不同的MgO含量下制备的碳纳米管形貌及结构进行了表征。结果表明,随着MgO含量的增加,从碳纳米洋葱转化为碳纳米管,其直径逐渐变小、均匀,碳纳米管纯度提高,结晶性能越好;碳纳米管顶端形成开口或闭口的碳洋葱纳米结构,而管的主干区域则存在催化剂,并且随着MgO含量的增加,呈现纳米颗粒转化为纳米线的趋势;MgO含量为50%时,部分碳纳米管的外壁剥离,形成了单原子石墨层,长度达到7nm,并在碳纳米管内部填充了Ni纳米线,其长度有60nm。

Growth characteristics of carbon nanotubes with Ni/MgO catalyst

Using Ni/MgO catalyst,carbon nanotubes(CNTs) were synthesized on silicon by radio-frequency plasma enhanced chemical vapor deposition(RF-PECVD) method.The morphologies and microstructures of the CNTs were characterized by X-ray diffraction(XRD),scanning election microscopy(SEM),Raman spectroscopy and high-resolution transmission electron microscopy(HRTEM).The results show that as the MgO content increases,carbon nano-onions transform into CNTs,the nanotube diameter becomes smaller and uniformity,the purity of CNTs is improved,and crystallinity is better;The top of the CNTs transforms open or closed carbon nano-onion structure,and in the backbone of the tube area,there exists cataly.With the increase of MgO content,the nano-particles change into nanowire.When the MgO content is 50%,the outer wall of part CNTs forms a single-layer graphite,its length is 7 nm,and the CNTs are filled with Ni nanowires whose its length is 60 nm.