Application of fly ash as a catalyst for synthesis of carbon nanotube ribbons

The larger diameter-based carbon nanotube (CNT) ropes and ribbons are currently synthesized by catalytic decomposition of hydrocarbons with transition metal-based catalysts e.g., Co, Ni, Fe and Mo at 1100-1200 degrees C, using chemical vapour deposition (CVD) and electric arc methods. We produced CNT ribbons by fly ash (FA) catalyzed pyrolysis of a composite film of poly (vinyl alcohol) (PVA) with FA at 500 degrees C for 10 min under a nitrogen flow of 2 L/min. Different geometrical structures, e.g.; knotted and twisted. U- and spiral-shaped CNT ribbons were observed in the images of scanning and transmission electron microscopy. The widths of the CNT ribbons measured varied in the ranges 18-80 nm. X-ray photoelectron spectroscopy analysis showed five types of carbon binding peaks, C-C/C-H (similar to 77%), C-O-H (similar to 9%), -C-O-C (similar to 5%), C=O (similar to 5%) and -O-C=O(similar to 3%). The ratio of intensities of G and D bands. IC/ID was 1.61 analysed by Raman Spectroscopy. CNT ribbons grown on the surface of FA have potential for the fabrication of high-strength composite materials with polymer and metal. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.