Influence of NH3 atmosphere on the growth and structures of carbon nanotubes synthesized by the arc-discharge method

Using the improved arc-discharge equipment, we selected graphite as electrode and prepared the multi-walled carbon nanotubes in an atmosphere of pure NH3 at pressure of 0.02 MPa and discharge current of 70 A by the arc-discharge method. The influence of NH3 atmosphere on the growth and structure of carbon nanotubes was studied. By analyzing transmission electron microscope and scanning electron microscope micrographs, we found that a large quantity of multi-wall carbon nanotubes can be grown on the top surface and in the inner of interlayer between central part and outer part in the cathode deposits. The results show that there is no significant difference of the shapes and the structures between NH3 atmosphere and other atmosphere such as He, H2, et al., except their positions. This study demonstrates that the arc-discharge method in NH3 atmosphere is one highly efficient method in the preparation of carbon nanotubes.