Nickel-aluminum (Ni/Al) mixed oxides located on multiwalled carbon nanotubes (MCNTs) are obtained by decomposition of hydrotalcitetype (HT) Ni/Al compounds prepared by coprecipitation method from the nitrate salts of the elements. Thermogravimetry analysis (TGA), temperature-programmed reduction (TPR), X-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques are used to study this system. Comparisons of decomposition process and of reducibility are made between MCNT-supported Ni/Al compounds or mixed oxides and those supported by diatomite. MCNTs react with Ni/Al mixed oxides to form Ni during calcination. Accordingly, the catalyst reduction process for nanotube synthesis based on MCNT-supported Ni/Al mixed oxides can be omitted. (C) 2003 Elsevier B.V. All rights reserved.