Large-area synthesis of carbon nanofibers and nanotubes on disk of Al₂O₃ by dip-coating

Particles of α-Al₂O₃ pressed in a mold followed by sintering at high temperature would form into a porous substrate. Fe and Ni catalyst was dip-coated on the surface of Al₂O₃ disk, with acetylene as carbon source, carbon nanofibers and nanotubes were synthesized on the disk by the chemical vapor deposition method. The products mainly contained carbon nanofibers (CNFs) and a little carbon nanotubes (CNTs). Diameter and yield of CNFs and CNTs increased approximately in direct proportion to the concentration of the dip-coated catalyst. Diameter of CNFs that grew on Ni catalyst was smaller than that of CNFs that grew on Fe catalyst. The products determined by X-ray diffraction are graphitic.