Spiral carbon tubes grown by a mixed-valent oxide-catalytic carbonization process
- Georgia Institute of Technology, Atlanta, GA (United States)
Synthesis of carbon tubes is vitally important in carbon research and applications. In this paper, spiral carbon tubes are grown by a mixed-valent oxide-catalytic carbonization (MVOCC) process. The carbon tubes are highly twisted and have many growth induced nodes. The product has high purity and no catalyst particle is found in the product. With the presence of inter-lock structure, the mechanical properties of the material made using the spiral carbon tubes could be significantly improved. The inner tube is not completely hollow but interconnected by graphic layers. The surfaces of the tubes have many open graphitic edges, thus, a high chemical activity of the tubes is expected. Figure 2 shows a log-magnification TEM image at the initiation side of a carbon tube, where a spiral node is formed. The non-uniform contrast across the node region reflects the spiral geometry at the node. In the growth front, the inner tube is not hollow and is interconnected by graphitic {open_quotes}bridges{close_quotes}. The graphitic layers composing the inner-wall region of the tube have larger sizes, while the graphitic flakes in the outer-wall region are rather small, with sizes ranging from 1-10 nm. The growth front has a shape similar to a {open_quotes}cowboy hat{close_quotes}, where the graphitic layers across the top of the hat are severely bent, indicating the non-equilibrium shapes at the growth front. A sharp turn of the graphitic layers at the edge of the hat may be produced by a {open_quotes}boat-type{close_quotes} line defect proposed for interpretation of a 90{degrees} bending of carbon layers. The alignment between graphite layers is also visible at the left-side of the hat, suggesting a coherent layer-by-layer growth at the growth front.
- OSTI ID:
- 468888
- Report Number(s):
- CONF-960877-; TRN: 97:001308-0145
- Resource Relation:
- Conference: Microscopy and microanalysis 1996, Minneapolis, MN (United States), 11-15 Aug 1996; Other Information: PBD: 1996; Related Information: Is Part Of Microscopy and microanalysis 1996; Bailey, G.W.; Corbett, J.M.; Dimlich, R.V.W.; Michael, J.R.; Zaluzec, N.J. [eds.]; PB: 1107 p.
- Country of Publication:
- United States
- Language:
- English
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