Directed synthesis of metal-catalyzed carbon nanofibers and graphite encapsulated metal nanoparticles

Directed synthesis of metal catalyzed carbon nanofibers and graphite encaps ulated metal nanoparticles is demonstrated where the catalyst metal nanopar ticles of Ni have been preformed prior to introduction into a reactive hydr ocarbon growth environment. Control of the chemical environment by additive s governs the type of product. Use of thiophene as an additive yields carbo n nanofibers, whereas chlorobenzene as an additive produces encapsulated me tal nanoparticles. Comparison of these results and those without any additi ve distinguishes the mechanism(s) by which each additive promotes nanotube or encapsulation, respectively.