Effect of hydrocarbon and transport gas feedstock on efficiency and quality of grown single-walled nanotubes
US8591858B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 1, 2008 |
| Grant date | Nov 26, 2013 |
| Priority date | — |
| Expiry date | Nov 7, 2029 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/2918
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
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 (IG:ID) 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.