The catalytic chemical vapour deposition (CCVD) of carbon nanotubes onto Fe-doped alumina catalysts, with varying iron concentrations and reaction times is described. Methane was used as a carbon source, and nanostructural growth was afforded at 1000 degrees C. Characterization of alumina-supported iron catalysts was done using N-2 adsorption-desorption measurement and X-ray diffraction. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used for characterization of resultant carbon nanotubes (CNTs). The SEM images indicate that diameter and length of as-produced CNTs depends on both iron content of the catalyst and reaction time; with lower iron concentrations, longer and thinner nanotubes were obtained. The yield of products was investigated by TGA, and showed that increasing the catalyst iron content and reaction time directly affect the amount of formed product. (C) 2009 Elsevier B.V. All rights reserved.