Allotropic Carbon Nanoforms as Advanced Metal-Free Catalysts or as Supports

Scheme 2

Pictorial illustration of the synthesis of CNT by dehydrogenative carbonisation of methane on hot metal nanoparticles. On the surface of the metal carbon atoms are continuously being formed at high temperatures due to the dehydrogenative decomposition of the precursors (methane in this case) and these atoms condense in an hexagonal arrangement leading to the graphene wall with diameter commensurate with the dimensions of the metal nanoparticle catalyst and growing outside these nanoparticles.