Abstract Submitted to the    NANOTUBE'04 Conference:

A new method was developed for mass-production of high crystallinity SWNTs at high-yield and low cost, and the produced SWNTs can be easily purified. This will accelerate the studies of physical properties and practical applications of bulky SWNTs. High-yield SWNTs have been prepared by arc discharge evaporation of carbon electrode containing 1.0 at.% Fe catalyst in hydrogen mixed gas (i.e., H2-inert gas, or H2-N2). When a whole C-Fe electrode (6 mm diameter, 100 mm long and 4 g mass) was evaporated (dc arc current, 50 A) for 20 min in 40%H2-60%N2 mixture gas under a pressure of 200 Torr, a huge SWNT web with the mass of more than 200 mg could be obtained. SEM, HRTEM and Raman spectroscopy studies indicate that SWNTs have high crystallinity, "clean" surface, and yield higher than 70 at.%. The high temperature of arc discharge favors the growth of high crystallinity SWNTs, and the steep temperature gradient hampers the formation of multiwalled carbon nanotubes. Moreover, because hydrogen atoms etch amorphous carbon during the formation of SWNTs, the coexisting Fe catalyst nanoparicles are embedded in very thin amorphous carbon. Therefore, the purification of SWNTs can be easily performed by heat treatment and rinsing by hydrochloric acid to obtain SWNTs with purity higher than 90 at.%.