<p>Methane pyrolysis at the temperature range of 550-1000 °C in gas flow reactor with fixed bed of mixed catalysts based on carbon materials of various structure (fullerene cocoons, fullerene black, vacuum black, cathode deposit, onion-like carbon, glassy carbon, carbon fibers, mineral shungite and graphite) has been studied. Methane pyrolysis products, including stoichiometric amount of hydrogen are C<sub>3</sub>-C<sub>4</sub> alkanes, C<sub>2</sub>-C<sub>4</sub> alkenes, aromatics and pyrolytic carbon. Methane pyrolysis is carried out both on a catalytic surface and in a volume and contribution of the surface is determined by pyrolysis temperature. Materials with curved carbon surface show an activity in methane dehydrogenation at lower temperatures, than materials with planar basic structure elements. Materials with a small specific surface area favor methane aromatization at 950–1000 °C with formation of mainly benzene, toluene and naphthalene. The primary activation of C–H bond in methane at temperatures of lower than 850 °C, as well as the multiple dehydrogenation conversions resulting in the formation of pyrolytic carbon and its precursors (aromatics), are, probably, heterogeneous reactions.</p>
This review concerns the fullerene black, a poorly known nano-sized carbon material, the insoluble residue after extraction of fullerenes from fullerene soot produced by arc evaporation of carbon material (usually graphite) in a helium atmosphere. This by-product of the production of fullerenes, whose yield reaches 80 wt %, is a finely dispersed material with a particle size of 40-50 nm. It includes amorphous carbon, graphitized particles, and graphite. Test reactions showed the presence in the structure of fullerene black of curved surfaces, and, like fullerenes, of alternating non-conjugated simple and double bonds. In addition to the double bonds, its structure includes dangling bonds in the concentration not higher than one per 1200 carbon atoms. This nano-carbon can not be graphitized, enters into the reactions of nucleophilic addition, and absorbs oxygen and water from the atmosphere. The fullerene black as was shown activate hydrogen and thus to undergoes to a hydrogenolysis without a catalyst and to catalyzes the dehydrogenation and dehydrocyclization of alkanes. This carbon nanomaterial can be used as a sorbent for organics, as a catalyst support, as a tribotechnical additive; and it can interact with carbide-forming metals and reinforces their surface.
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