镍粒子在单壁碳纳米管生成中的催化机制

用CVD法制备单壁碳纳米管，一般加入镍金属颗粒作为催化剂，由于镍金属颗粒不同晶体表面对碳原子的吸附具有不同的活性，在制备单壁碳纳米管时，导致镍颗粒（液态）吸附的碳原子在其表面由活性小的晶面活性大的晶面扩散并沉积，结果围绕镍金属颗粒形成空腔，单壁碳纳米管得以生成，在单壁碳纳米管生长过程中，镍原子作为替位式原子，总是处在碳纳米管六角网络的最外端，起着缺陷稳定剂的并促进其生成，笔者阐述了镍金属颗粒催化剂的催化机制，并对单壁碳纳米管产物的形貌作了合理解释。

Catalytic Mechanism of Ni Particles in the Formation of Single-Wall Carbon Nanotubes

Usually Ni_clusters are served as catalyst in the formed processo f the single_wall carbon nanotubes by CVD. Because the different surfaces of Ni_clusters have different activity,carbon atoms adsorbed in Ni_clusters (liquid states)will be diffused from low_activity surfaces of Ni_cluster to high_activity ones and be deposited. As a result,the caves of carbon atoms surrounding the Ni_clusters are formed and the single_wall carbon nanotubes are produced. In addition,Ni_atoms served as substitutional atoms always located in the furthest outside of the network of single_wall carbon nanotubes are produced. In addition, Ni_atoms served as substitutional atoms always located in the furthest outside of the network of single_wall carbon nanotubes,and play a role of stabilization in growth of nanotubes,and promot their growth. Therefore,the catalytic mechanism of Ni_clusters as catalyst is introduced,and different morphologies of single_wall carbon nanotubes are also exlained.