One-Step Liquid-Phase Synthesis of Carbon Nanotubes with Catalyst Precursors of Organometallic Complexes

This paper describes a simple, low cost one-step liquid-phase process for the synthesis of highly aligned carbon nanotube (CNT) arrays (HACNTAs). Highly pure HACNTAs were grown on a stainless steel substrate by resistance-heating in methanol solution containing one of the organometallic complex catalyst precursors, ferrocene Fe(C5H5)(2) and iron pentacarbonyl Fe(CO)(5). Effects of the catalyst precursors on the formation and morphologies of HACNTAs were examined. A small amount of non-aligned multi-walled CNTs (MWCNTs) were grown from 1mM Fe(C5H5)(2) methanol solution. Highly pure HACNTAs composed of MWCNTs were readily grown from 10 and 40mM Fe(C5H5)(2) methanol solutions by this one-step liquid-phase process. From the Fe(CO)(5) methanol solution, HACNTAs were prepared even at a very low Fe(CO)(5) concentration of 0.01 mM, which was about 1/1000 lower than that of Fe(C5H5)(2). The optimal low concentration is attributed to the low decomposition temperature of Fe(CO)(5). (c) 2011 The Japan Society of Applied Physics