An efficient and inexpensive method for the production of multi-wall carbon nano tubes by the thermal plasma route

Abstract

An extended argon arc plasma reactor has been utilised for efficiently producing multi-walled carbon nano tubes (MWCNT) with an inexpensive raw material such as the calcined petroleum coke. In this investigation, CPC powder was dry mixed with 2.5 wt %, Ni catalyst in a ball mill and the resulting homogeneous raw material mixture was heat treated in a graphite crucible in a vacuum argon arc plasma reactor for the duration of 30 minutes. It was noted that carbon nano tubes (CNTs) were deposited on a relatively cooler portion of the plasma reactor, with a yield of 15 wt %, with respect to the total weight of the charge. The extensive characterization of the carbon nano-tubes was carried out through micro-Raman, X-ray diffraction and transmission electron microscopy techniques. The XRD studies on the CNTs, produced by the above method showed 100% peak at d(002) value of 3.39 angstrom and other peaks of 4-H graphite. The d- band and g- band reflections observed in the Raman spectrum of CNTs also showed graphite as a major and cubic diamond as a minor phase. The TEM studies on the plasma processed and purified CNTs, showed aspect ratio of 15 to 16 and an average diameter of 3.4 nm.