Carbon can be in several forms. Amorphous, graphite and diamond. Fullerenes are accepted as the fourth form of solid carbon. They are basically, large carbon cage molecules. By far the most common one is C60. Nanotubes are actually longer forms of fullerenes.
If a voltage is applied between two carbon rods, an arc will develop between them. If the arc is maintained in helium or argon (instead of air) clouds of black carbon powder is produced. Although many studies have been performed on cathodic deposits, (i.e. nanotubes first seen in this section) very few studies on the carbon sooth are found in the literature. Only around 10% of the black soot is fullerene, the composition of the remainder varies depending on the working conditions. But it is assumed to contain parts of various fullerene particles even higher fullerenes up to C300. This fraction is abbreviated as FES through the thesis.
This work comprises the production of FES (fullerene extracted soot), soot, cathodic deposit produced under nanotube conditions and cathodic deposit produced under fullerene conditions and characterization of these in terms of their specific surface areas / pore volume distribution, porosity and as a second part, adsorption capacity of gases H2 and NH3 have been found.
Both physical and chemical adsorption analyses were done using Quantichrome Autosorb 1-C surface analyzer. Obtained isotherms for nitrogen adsorption were found to be in between type II and type IV. BET surface areas for the samples of FES and soot prepared under nanotube conditions and cathodic deposit prepared under fullerene and nanotube conditions were found 240, 180, 14.6 and 29.7 m2/g of surface area respectively. Micropore volumes were calculated from Horwath - Kowazoe and Saito - Foley methods were found 0.045, 0.034, 2.38*10-3 and 1.19*10-3 cc/g respectively. Active surface areas for NH3 adsorption were found for FES, soot and Norit active carbon sample are found to be 39.2, 49.6, 32.5 m2/g at 300 C and 6.35, 14.65, 6.59 m2/g at 3000 C respectively.
As a result of this work, it is concluded that although not superior to NORIT CN1 active carbon sample, FES is as active as that material and able to adsorb as much hydrogen as active carbon. This is important because FES is already a side product of the arc-evaporation fullerene production technique and has no known uses at all.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12606671/index.pdf |
| Date | 01 August 2005 |
| Creators | Ok, Sinan |
| Contributors | Ozbelge, H. Onder |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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