Iron-cobalt catalysts synthesized by a reverse micelle impregnation method for controlled growth of carbon nanotubes

Fe-Co bimetallic metals supported on CaCO3 support have been prepared using three different methods for the preparation of the catalysts; wet impregnation (IMP), deposition-precipitation (DP) and reverse micelle impregnation (RM). By careful choice and optimization of CVD reaction conditions and catalyst preparation procedures, we have tailored the nanofabrication of CNTs using 5 wt.% Fe-Co/CaCO3. High yields of 'clean' MWNTs with near 100% selectivity and excellent reproducibility were obtained (1215% and 835% yields for the IMP and DP methods respectively). The RM technique enabled more precise control over the size of the CNTs and a narrower diameter distribution (3-5 nm i.d. and 10-15 nm o.d.) was obtained. (C) 2008 Elsevier B.V. All rights reserved.