Large scale synthesis of carbon nanotubes by plasma rotating arc discharge technique

摘要

The large-scale synthesis of carbon nanotubes is achieved by plasma rotating arc discharge. The graphite anode is rotated at a high velocity for the synthesis of carbon nanotubes. Conventional arc discharge is an unstable process because of the cathode spot phenomena, which induces an inhomogeneity of the electric field distribution and a discontinuity of the current flow. The rotation of the anode distributes the microdischarges uniformly and generates a stable plasma. The centrifugal force by the rotation generates the turbulence and accelerates carbon vapor perpendicular to the anode. It is not condensed at the cathode surface but collected on the graphite collector that was placed at the periphery of the plasma. The nanotube yield increases as the rotation speed of the anode increases and the collector becomes closer to the plasma. The reason for this is because two conditions are optimized. One is the high density of carbon vapor that is created yb uniform and high temperature plasma for nucleation and the other is the sufficient temperatue of collectors for nanotube growth. The plasma rotating electrode process is a continuous process of the stable discharge and it is expected to perform the mass production of high quality nanotubes.