Abstract Submitted to the    NANOTUBE'04 Conference:

Results from mechanistical investigations of SWCNT synthesis via aerosol method in vertical ambient pressure laminar flow reactor are presented. Catalyst nanoparticles were obtained via ferrocene (vapour pressure p=0.7 Pa) and iron pentacarbonyl (p=0.3-4 Pa) decomposition and utilised in combination with CO (p=1 atm) and ethanol (p=200 Pa in N₂) to produce SWCNTs. Experiments were carried out at 800-1300oC with the average residence time of 3-6 seconds in the reactor. The product properties were studied by TEM imaging and on-line aerosol number size distribution measurements. The metal catalyst particle size was controlled by the metal precursor vapour concentration, the rate of particle formation via temperature of metal precursor feed, and the residence time. Iron pentacarbonyl decomposition in CO led to excessive catalyst particle growth and yield of SWCNTs was low. The morphology of the product from ferrocene was varied depending on t he carbon precursor and reaction temperature, i.e. abundant SWCNT formation was observed from CO disproportionation between 900-1150oC, while ethanol decomposition resulted in the formation of SWCNTs at 950oC and carbon fibers at 1150oC. Mechanisms of SWCNT formation and growth are proposed based on detailed characterisation of the reactor conditions via computational fluid dynamics calculations and analysis of the experimental data.