particles generated in examples 5 and 6 were the right size to promote swnt growth over the other forms possible in example 4 particle sizes favored growth of mwnt and other forms in a direct injection process the catalyst compartment was loaded with u02dc 40 mg molybdenum hexacarbonyl mo co 6 which has been ground to u02dc u2212 100 mesh the reactor was heated to 900 u00b0 c under an argon flow argon was then replaced with co at atmospheric pressure at a flow of u02dc 0 8 slm and the catalyst was injected the flow of co was continued for 30 min at 900 u00b0 c after which it was replaced by argon and the reactor furnace turned off after cooling to ambient temperature the entire contents of the reactor including the quartz wool plug which had been tared prior to the run was emptied into a tared plastic bag the quartz wool plug was blackened but the yield of carbon growth wgt c wgt catalyst was lt 1 a specimen for transmission electron microscopy tem was prepared by shaking the quartz wool plug in ethanol in a glass vial and ultrasounding the ethanol for u02dc 2 min this procedure dispersed the black particles from the quartz wool a tem grid was prepared by evaporating several drops of this dispersion onto a carbon coated copper grid examination of the grid in the tem showed a mixture of particles and carbon nanotubes both mw and sw particles varied from u02dc 1 several hundred nm and were shown to be mo by.