Synthesis and characterization of multi- and single-wall carbon nanotubes by the catalytic vapor deposition method

Abstract

Carbon nanotubes (CNTs) have been synthesized by catalytic decomposition of acetylene (catalytic chemical vapor deposition, the so-called CCVD method) over well dispersed metal particles (cobalt and iron) embedded in supports such as commercially available zeolites and folded sheets mesoporous material (FSM) at temperature above 600°C. A few individual single-wall carbon nanotubes (SWNTs) and bundles of SWNTs are observed in pristine soot synthesized with FSM supports at 900°C, whereas no SWNTs but only multi-wall CNTs (MWNTs) are observed in pristine soot synthesized at less than 800°C. The observed temperature dependence is similar to the synthetic result obtained with zeolites supports. The yield of CNTs (both SWNTs and MWNTs) is higher with Zeolite supports than with FSM. Transmission electron microscopy and Raman spectroscopy also revealed that surface pores of support materials could act as an excellent growth sites for SWNTs.