Carbon nanofiber microspheres obtained from ethylene using FeCl₃ as the catalyst precursor

Carbon nanofiber microspheres (CNFMSs) were synthesized from ethylene using FeCl₃ as the catalyst precursor. The CNFMSs were characterized by SEM, TEM, SEAD, EDS and Raman spectra. The as-grown CNFMSs were about 5 μm in diameter. The size of CNFMS was decreased to 1.5 μm by sonication. They were consisted of CNFs with a diameter less than 70 nm. The inner core of these CNFMS was composed of highly curved CNFs, the tortuosity factors of which were about 1.75 ± 0.20. The HRTEM image and the corresponding SAED pattern confirmed the herringbone structure of the CNFs. The ratio of I_D/I_G of the CNFs was 0.74. The EDS spectra showed the existence of Fe and Cl from the catalyst precursor in the CNFMSs. The iron catalyst was seriously poisoned for the high Cl:C ratio in the FeCl₃ as catalyst precursor in the floating catalyst process, then curved CNFs were grown. With the continuous feeding, most newly grown CNFs will interact with an already grown host CNF sphere to form a CNFMS. Then a simple strategy to prepare CNFMSs with inexpensive reagents was provided, which enhanced the potential uses of CNFs in a wide range of fields.