Abstract: A series of W-Fe-MgO catalysts with high BET surface area were prepared by mixing Mg(NO3)2•6H2O,ammonium tungstate, citric acid, Fe(NO3)3•9H2O and H2O,followed by drying at 150 ℃ and decomposing at 550 ℃.Using these catalysts, bundled SWCNTs with diameter 1～3 nm for each tube, were synthesized in a fluidized reactor. The maximum yield of SWCNTs was 36 mg/100 mg. TEM, micro-Raman and TPO (temperature programmed oxidation) results showed that the products were SWCNTs of high purity and almost defect-free. From the EDAX results and phase-diagram of W-Fe, we deduced that the active phase for SWCNTs growth was a solid solution or an intermetal compound of tungsten and iron.

Key words: Single-wall carbon nanotubes (SWCNTs), W-Fe-MgO, Fluidized bed,CCH4 decomposition