Plasma Synthesis of Fullerenes

Churilov, G.N. (2000) Plasma synthesis of fullerenes, Instr. Experim. Tech. 1, 1-10. 

Plasma Nanotechnologies Synthesis of Fullerenes and Carbon Nanotubes... 

PLASMA NANOTECHNOLOGIES SYNTHESIS OF FULLERENES AND CARBON NANOTUBES... 

Synthesis of Fullerenes. As mentioned above, the experiments leading to the first observation of the fullerenes involved the formation of carbon vapor plasma by... 

The Ba.C) N, nanotubes and fullerene-like structures have been synthesized by various laboratories in recent years. The most popular method is the plasma arc technique. The first report on the synthesis of BN nanotubes was by Zettl and coworkers (55). Since BN is an insulator, a composite anode was prepared from a tungsten rod with an empty bore in the center, which was stuffed with a pressed hexagonal BN powder. For the cathode, a water-cooled Cu rod was used. The collected gray soot contained limited amount of multi wall BN nanotubes. It is possible that in this case, the tungsten serves also as a catalyst. By perfecting this method, macroscopic amounts of double-wall BN nanotubes of a uniform diameter (2 nm)... 

Continuous production of fullerenes was possible by pyrolysis of acetylene vapor in a radio-frequency induction heated cylinder of glassy polymeric carbon having multiple holes through which the gas mixture passes [44]. Fullerene production is seen at temperatures not exceeding 1500 K. The yield of fullerenes, however, generated by this method is less than 1%. A more efficient synthesis (up to 4.1% yield) was carried out in an inductively coupled radio-frequency thermal plasma reactor [45]. 

Other derivatives of [60]fullerene that have been the subject of substantial attention are the alkali-metal fullerides - mainly since the discovery of superconductivity in K3C60 (66). Synthesis of these systems usually involves combination of stoichiometric quantities of alkali metal and Ceo- Solid-state synthesis required long reaction times, however - typically several days. Use of a microwave-induced argon plasma led to reaction times in the order of seconds [68]. 

BN and B cCj,N2 nanotubes and fullerene-like structures have been synthesized by various laboratories in recent years. The most popular methods are the plasma arc and laser ablation techniques. The first report on the synthesis of BN nanotubes, using the arc-discharge technique, was by the Zettl group [85, 86]. Because... 

Since their discovery by Ijima in the early nineties as a byproduct of fullerene synthesis [1], carbon nanotubes have received a growing interest. A huge number of synthesis routes have been proposed, ranging from laser ablation of carbon target, catalytic chemical vapour deposition (CCVD), liquid phase synthesis, plasma methods, and so forth [2]. Also, a large variety of application niches have been identified that render nanotubes a promising material [3]. 

Polymeric fullerene materials can be obtained by many methods, for example by irradiation with electrons or ions, treatment in a plasma generator, doping with alkali metals [9,28,46], direct chemical synthesis [47], or mechanical milling [29]. Because of the small penetration depth of light fullerenes can only be photopolymerized as thin films, but bulk photopolymer can be obtained by polymerization in solution [48,49]. Diffraction studies show that photopolymers usually have a disordered fee structure. Although some ordered films have been... 

All samples were obtained in the setup for fullerene synthesis by the technique described earlier [4-5], Novelty of this technique was that materials were produced in plasma-chemical reactor without air access and they shifted to the chamber for the sample investigation, see Fig. 1. 

Thus, high fullerene yield at 44 kHz may be explained by the occurrence of electron concentration oscillations in the plasma. That such electron concentration oscillations are highly affecting the fullerene synthesis is known. For details see [8],... 

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