South African Journal of Chemistry
On-line version ISSN 1996-840X
CAO, Yong et al. Synthesis of nitrogen-doped carbon nanotubes with layered double hydroxides containing iron, cobalt or nickel as catalyst precursors. S.Afr.j.chem. (Online) [online]. 2010, vol.63, pp. 58-61. ISSN 1996-840X.
Nitrogen-doped carbon nanotubes (CNx) were synthesized by the catalytic chemical vapour deposition of ethylenediamine with layered double hydroxides (LDHs) containing iron, cobalt or nickel as catalyst precursors at 650 °C. The catalytically active metal particles were obtained by calcination of LDHs followed by reduction. X-ray diffraction was used to characterize the structures of the precursors and their calcined products. Transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to characterize the grown CNx. The results show that the CNx grown with Mg2 Fe-LDH as catalyst precursor have abamboo-like morphology and large diameter, while hollow tubes are obtained with CoMgAl- and NiMgAl-LDH as catalyst precursors. The CNx grown with CoMgAl-LDH have the highest N-doped content and the CNx grown with NiMgAl-LDH have the highest degree of graphitization among these three products.
Keywords : N-doped carbon nanotubes; layered double hydroxides; chemical vapour deposition.