Abstract
Carbon nanotubes were synthesized using a CVD floating feed method with a vertical reactor. The effect of the reaction temperature, pressure, and compositions of the feedings on the production rate and quality of the carbon nanotubes are discussed. The feed mixtures included the following components: (1) nitrogen as a carrier gas; (2) Fe(CO) 5 as a catalyst; and (3) methane as a source of carbon. Under limited operational conditions, a maximum yield of carbon products of 3.5 g/h with CNT purity of approximately 30% could be achieved by feeding 250 sccm. methane, 1000 sccm nitrogen, and Fe(CO) 5 at 0.5 mL/h and 1100°C, with 1 atm. The results suggest that CNTs can be fabricated using the CVD method in the absence of substrate, and that this approach is cost-efficient and safer in terms of the operational environment with nitrogen used as a carrier gas. Moreover, the vertical reactor can be scaled up for continuous mass production carbon nanotubes.