High-Rate Synthesis of Carbon Nanostructures in Oxy-Flames

1. High-Rate Synthesis of Carbon Nanostructures in Oxy-Flames Lawrence A. Kennedy, MIE; Alexei V. Saveliev, MIE Primary Grant Support: National Science Foundation, Air Liquide • Carbon nanotubes are materials of the future and synthesis techniques are required for their high quality production at commercial rates • At present, oxy-flames are the major industrial source of pyrolytic (black) carbon. The development of high-rate synthesis method of carbon nanotubes and carbon nanofibers with controlled structure and morphology will open new horizons stimulating numerous applications requiring large volumes of carbon nanomaterials • Formation of carbon nanomaterials in opposed flow flames of methane and oxygen enriched air is studied experimentally at various oxygen contents • A catalytic probe is introduced in the flame media, the products are analyzed using transmission and scanning electron microscopy • An electric field control of carbon nanomaterial growth is implemented applying combinations of internal and external fields • A model of carbon nanotube interaction with electric field is developed and applied for the result interpretation • The method of high-rate synthesis of vertically aligned CNTs with high purity and regularity has been developed • It is shown experimentally that application of controlled electrostatic potential to a catalytic probe in a flame induces uniform growth of CNT layer of multi-walled nanotubes • The mechanism of the electric field growth enhancement has been studied experimentally and theoretically. It is found that the major influence of the electric field is related to the polarization alignment of growing nanotubes and charge induced stresses acting on the catalytic particles