AVS 47th International Symposium
    Nanotubes - Science and Applications Tuesday Sessions
       Session NM+NS-TuM

Paper NM+NS-TuM9
A Gas-Phase Method for Large-scale Production of Carbon Single-walled Nanotubes

Tuesday, October 3, 2000, 11:00 am, Room 309

Session: Carbon Nanotubes: Synthesis
Presenter: M.J. Bronikowski, Rice University
Authors: M.J. Bronikowski, Rice University
R.K. Bradley, Rice University
P.A. Willis, Rice University
D.T. Colbert, Rice University
K.A. Smith, Rice University
R.E. Smalley, Rice University
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We have demonstrated large-scale production of high-purity carbon single-walled nanotubes (SWNT) using a gas-phase CVD process we call the HiPCO process. SWNT grow in high-pressure (10 - 100 atm), high-temperature (700 - 1200 °C) flowing CO, on clusters of catalytic metals such as iron and nickel. The metal clusters are formed in situ: metal is added to the gas flow in the form of organometallic compounds such as Fe(CO)@sub 5@ and Ni(CO)@sub 4@. Upon heating, the organometallics decompose and the metal atoms condense into clusters of 10 - 100 atoms. These clusters serve as catalytic particles upon which SWNT nucleate and grow (in gas phase) via CO disproportionation: CO + CO -> CO@sub 2@ + C(SWNT). SWNT material of up to 99 mole-% purity has been produced at rates of up to 350 mg/hr. The dependence of the quantity and quality of SWNT material produced on parameters such as temperature, pressure, catalyst concentration, catalyst composition and the presence of various catalyst enhancers (e.g., hydrogen and sulfur) will be discussed. The HiPCO process is currently being optimized and scaled for bulk production of 10 - 100 grams/day of high-purity SWNT material.