We report a high-yield route to two-dimensional arrays (<400×400 μm2) of aligned C49Nx (x⩽1) nanofibers (<100 nm o.d.; <60 μm length), by pyrolyzing mixtures of ferrocene and melamine at 950–1050 °C under an Ar flow. The fibers exhibit unusual interlinked stacked-cone morphologies, ascribed to the presence of nitrogen. High-resolution electron energy-loss spectroscopy of the individual fibers reveals a 2% nitrogen content with ionization energies mainly at ∼400.9 eV, corresponding to N bonded to three C atoms within a hexagonal framework. The nanofibers may be useful for the economic fabrication of field emission sources and robust composites.

Arrays of aligned nanotubes of large diameter (100–250 nm) are synthesized by pyrolyzing a jet (spray) solution of Fe(C5H5)2 and C6H6 in an Ar atmosphere at relatively low temperatures (850 °C). The tubular structures consist of highly crystalline nested graphene cylinders (<200 concentric tubes) with tips that are usually open. Raman studies confirm the high degree of perfection of these “thick” structures. Tube diameter, degree of alignment, and crystallinity can be controlled by varying the Ar flow rate and the Fe:C ratio within the precursor solution. Based on these observations a possible growth mechanism is suggested. This low cost route for the synthesis of carbon nanotubes is advantageous due to the absence of H2 as a carrier gas and the low pyrolytic temperature.

No abstract

No abstract

No abstract