Electronic state of carbon in nanostructured composites produced by co-carbonization of aromatic heavy oil and ferrocene

The electronic state of carbon in the products of co-carbonization of an aromatic heavy oil and ferrocene in an autoclave has been studied by X-ray emission spectroscopy. Analysis of the C Kα-spectra revealed that the proportion of graphite-like component in the samples containing ferric spherical and tubular nanoparticles is about 55% and 65%, respectively. An average size of graphitic sheets forming the coating on metallic cores and the carbon matrix was estimated by the results of quantum-chemical calculations on graphene fragments to be ∼2 nm. The field electron emission properties of the studied carbon materials were found to be dependent on the graphitization degree, not on the aspect ratio of constituting nanoparticles.