Abstract
The template synthesis and characterization of carbon nanotubes (CNTs) formed in porous alumina membranes (PAM) by the thermal chemical vapor decomposition (CVD) of propylene (Pr) gas are described. We found that the graphitic character of CNTs improved as CVD temperature was increased from 500 to 800°C. Samples showed progressive increases in metallic appearance and layered tube wall structure and decreases in electrical resistance. No further enhancement of graphitization was observed among samples formed at 800, 900 and 1000°C. X-ray diffraction (XRD) indicated that long-range order was absent in all CNTs tested. Localized crystalline domains of graphitic carbon, however, were detected by Raman spectroscopy and seen in light and dark field transmission electron microscopy (TEM) images. CNTs formed in the presence of catalytic Fe and Co particles at 600 and 700°C with a Pr/N2 flow rate of 94 sccm (standard cubic centimeters per minute) showed slightly lower electrical resistance than CNTs formed in control experiments. The catalytic effects of Fe and Co were observed for samples made at 800°C with a 50 sccm Pr/N2 flow rate as 'nanotubes within nanotubes' were formed. No major differences were found between catalyst-containing and control samples formed at temperatures greater than or equal to 800°C at 94 sccm.
Original language | American English |
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Pages (from-to) | 83-88 |
Number of pages | 6 |
Journal | Nanostructured Materials |
Volume | 12 |
Issue number | 1 |
DOIs | |
State | Published - 1999 |
Event | Proceedings of the 1998 4th International Conference on Nanostructured Materials (NANO '98) - Stockholm, Swed Duration: 14 Jun 1998 → 19 Jun 1998 |
NREL Publication Number
- NREL/JA-590-27883