Tailoring the diameters of vapor-grown carbon nanofibers

Diameters in the range 40-300 nm for vapor-grown carbon nanofibers (VGCNFs) can be tailored using synthesis parameters with a Roaring catalyst method at temperatures of 1373-1473 K in the presence of sulfur. The VGCNFs obtain ed are found to be very pure and straight, and have uniform diameter within each batch for certain parameters. A lower molar ratio of C/H. appropriate molar ratio of S/C, and suitably higher flow-rate of the mixture of hydrog en and benzene help the growth of carbon nanofibers with smaller diameters. If the synthesis parameters are carefully controlled, our results show tha t VGCNFs with diameters of 5-40 nm can also be obtained. (C) 2000 Elsevier Science Ltd. All rights reserved.