Carbon nano-rod as a structural unit of carbon nanofibers

The structure of carbon nanofiber (CNF) with platelet texture was found to be constructed by a primary structural unit named carbon nano-rod by the authors through comprehensive examination of X-ray diffraction (XRD), high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron microscopy (HR-TEM), and scanning tunneling microscopy (STM). Single carbon nano-rod resembles multi-walled carbon nanotube with 4–5 graphene sheets nested (ca. 2.5 nm diameters), but appears to have a hypothetical transverse of hexagonal shape with the inner diameter corresponding to the interlayer spacing. Three-dimensional model of CNF was suggested based on the carbon nano-rods, which are densely stacked perpendicular to the fiber axis to form a typical platelet CNF. Such a structural concept of CNF gives novel views on the correlation between structure and properties of CNFs for potential applications.