Fe-Mo-Mg-O catalyst prepared by combustion method has great efficiency to grow carbon nanotubes with CVD method. Through investigation of TEM, it is found that bundles of multi-wall carbon nanotubes (MWCNT) can be got when the catalyst is directly used to synthesize the product in CH 4/H 2 atmosphere; however, the dispersed carbon nanotubes are obtained while the catalyst is reduced firstly in the H 2 before the synthesis. The morphology and structure of the catalysts before and after reduced are analyzed by TEM and XRD. The growth mechanism is suggeested for the formation off these two kinds of carbon nanotubes.
