Contrast Study Of Single-Wall Carbon Nanotube Synthesis By Different Condition

With remarkable structural, physical and chemical properties, single-wall carbon nanotubes (SWNTs) can be explored to be used in novel applications and become a hotspot of studies on nano material. Since the discovery of in 1993, the synthesis, purification and characterization of SWNTs have been an area of intense research. The one important way to produce low cost and large amount of SWNTs is to find effective and available catalyst and carbon source, so different of high carbon-contained solid source and the ferric compounded material as catalysts to produce high quality SWNTs by arc discharge were investigated, at the same time the affection of process parameters, carbon source and catalyst to synthesis SWNTs was studied in this paper. Therefore, the morphology, structure and purity of SWNTs were characterized by SEM, HRTEM, FTIR, XRD and Raman spectrum.The main conclusions are summarized as follows: the graphite level of carbon source play an important role in the purity and integrated of SWNTs, with the result that SWNTs prepared from graphite achieved the highest quality and the most purity, the result of charcoal was worse and carbon black was worst, but with the condition of electric current about 100A, gas pressure of argon about 200Torr-300Torr, charcoal as carbon source and FeS as catalyst, a grate number of web-like and cloth-like material could be found in reaction chamber, the curled and tangled SWNTs were found in these two materials under the observing of SEM and HRTRM, in addition with a little concomitant carbon nano-particle. We produce carbon nanotubes by three different rank coals, it is found that the type of coal and character of coal play an important role in quantity of carbon nanotube, anthracite is good of production of carbon nanotubes, lignite is not good of the production of carbon nanotubes.Considering the choice of technology condition, the activity of Fe₂O₃, Fe₃O₄, Fe and FeS were studied, the use of FeS (20wt%) could got best effect, the mixture of Fe and S with varies ratios were also used, it was found that Fe play a main role in catalysis and the adding of S could increase the quantity of SWNTs. It was advantage to select Ar (200Torr-300Torr) on preparing SWNTs by charcoal, and N₂ was not easy to synthesis carbon nanotube by charcoal. The production from continuous synthesis plant contained a great deal of concomitant carbon nano-particle, so the method was disadvantage to made carbon nanotube.