Simultaneous Production of Hydrogen and Filamentous Carbon

Schematic representation of carbon filaments of different structure produced by metal-catalyzed decomposition of methane, (a) Platelet structure, (b) herringbone structure, and (c) ribbon structure. MP denotes a nanosized metal particle. 

Li et al. [Ill] reported the simultaneous production of hydrogen and nanocarbon by decomposition of methane on Ni and Ni-Cu catalysts. The authors demonstrated the production of hydrogen with a purity of 80 vol% over 10 h simultaneously, 180 g of nanotubes 

TEM images of carbon filaments produced by decomposition of NG over Fe(10 wt%)/Al203 catalyst at 850°C. (a) Carbon filaments with embedded iron nanoparticles, (inset b) high-resolution TEM image of the wall of a carbon filament, and (c) = an iron nanoparticle encapsulated in carbon layers at the tip of a carbon filament. 

A series of kinetic studies on the carbon filament formation by methane decomposition over Ni catalysts was reported by Snoeck et al. [116]. The authors derived a rigorous kinetic model for the formation of the filamentous carbon and hydrogen by methane cracking. The model includes the following steps  

The rate-determining step is the abstraction of the first hydrogen atom from molecu-larly adsorbed methane with the formation of an adsorbed methyl group. Based on this 

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