Competitive Reactions During Plasma Arcing of Carbonaceous Materials

Abstract

Fullerene and pencil production has been studied by electrical arcing in various atmospheres. A range of different materials have been used as anode and the products have been studied using high-pressure liquid chromatography, gas chromatography-mass spectrometry, stable isotope mass spectrometry, and electron and light microscopy. In a methane atmosphere with graphite, the residual methane carbon is isotopically heavy because lighter methane is consumed. A different result is obtained with anodes containing hydrogen because the anode generates light methane, and depending on the amount of available hydrogen the carbon of the product gas can be slightly isotopically lighter or heavier than the original anode material. When materials containing hydrogen are used as anode, polycyclic hydrocarbons are produced. This is also true if graphite is used with a hydrogen atmosphere. It appears that different ratios of polycyclic hydrocarbons are produced when different materials are used as anodes. The results offer strong evidence that fullerenes can form from materials other than graphite through a process which does not involve total breakdown to individual carbon atoms.

Development of Catalyst Free Carbon Nanotubes from Coal and Waste Plastics

“…Figure 11 shows TEM micrograph of Samla SCC showing CNT of about 6-8 nm diameter and nanoparticles. (32) had also made the similar observations in their studies on the production of CNTs from coal. It also has been found that Assam coal produced spherical nanoparticles of comparatively larger size than those obtained from other coal samples (Fig.…”

In situ tracking of defect healing and purification of single-wall carbon nanotubes with laser radiation by time-resolved Raman spectroscopy

“…This was not observed, yet, their supposed contribution to G would rapidly decrease with the rst curing steps, since these molecules are highly volatile under laser radiation 46 and they can be incorporated in further tube growth. 47 Again, to circumvent the inaccuracies that may accompany the I D /I G + ratio, I G 0 /I D complements the characterisation. These two parameters, common indicators of defect and purity states, experience a 92% and 1180% improvement (at I 1 ), respectively, with respect to the pristine material (at I 0 ).…”

Stereochemistry of carbon nanotubes for electronic applications

“…That is, all bonds in the processed material do not have to be broken during arcing. We have recent confirmation of this mechanism from plasma arcing experiments using naphthalene as fill in hollow graphite tubes in order to simulate the way fullerenes and nanotubes might be formed from polycyclic hydrocarbons in coaI 9 ,1O. The results show that naphthalene in the plasma arc fringe increases the C70 to C60 fullerene ratio in the product soot and also increases the void space in the formed multiwalled nanotubes.…”