Importance

Loading Importance Indicators...

Abstract

Methods and processes for synthesizing high quality carbon single-walled nanotubes (SWNTs) are provided. The method provides the means for optimization of amount of carbon precursor and transport gas per unit weight of catalyst. In certain aspects, methods are provided wherein a supported metal catalyst is contacted with a carbon precursor gas at about one atmosphere pressure, wherein SWNTs are synthesized at a growth rate of about 0.002 μm/sec to about 0.003 μm/sec and the SWNTs have a ratio of G-band to D-band in Raman spectra (I_G:I_D) of greater than about 4. Efficiencies of about 20% can be achieved when contacting the catalyst deposited on a support with a carbon precursor gas with a flow rates of about 4.2×10⁻³ mol CH₄/sec·g (Fe) at 780° C. Hydrocarbon flow rates of about 1.7 10⁻² mol CH₄/sec·g (Fe) and higher result in faster carbon SWNTs growth with improved quality. Slower rates of carbon atoms supply (˜4.5×10²⁰ C atoms/s·g Fe or 6.4×10⁻⁴ mol CH₄/sec·g (Fe)) result in the formation of more defective nanotubes.

Loading the Abstract Image...

First Claim