Solid-state pyrolyses of metal phthalocyanines : A simple approach towards nitrogen-doped CNTs and metal/carbon nanocables

Solid-state pyrolysis of organometallic precursors has emerged as an alternative method for preparing carbon nanostructures such as carbon nanotubes (CNT) and carbon anions. The morphology of the tubes can be controlled by the nature of the precursors and the pyrolysis procedures, and micrometer long nanotubes, composed of metal carbide wires encased in a graphitic sheath. Cobalt phthalocyanine (CoPc) as well as iron phthalocyanine were pyrolyzed at different temperatures to obtain CNTs. HRTEM and energy-dispersion X-Ray analysis disclosed that the core consisted of long, iron-containing single crystals and that the core was fully surrounded by crystallized graphic carbon. Iron-filled carbon nanotubes were also obtained from the pyrolysis of ferrocene by CVD method. Encapsulated iron carbide were also observed inside the carbon nanotubes formed after pyrolysis of FePc. These nanotubes and nanocables were considered useful for assembling miniaturized electronic device and sensors.