The preparation of various nano-sized carbon materials (NCMs) using a metal dusting process, in which a stainless steel coupon and CO-CO(2) mixed gas are the only reactants needed, is demonstrated in this study. During the process, fresh Fe-Ni nano-particles, which catalyze the formation of the NCMs, are produced spontaneously and continuously from the steel. The possibility of using multi-wall carbon nanotubes (CNTs) prepared at 600 degrees C as a hydrogen storage material is studied. our electrochemical testing results indicate that the obtained CNTs have a hydrogen discharge capacity of as high as 104 mAh/g after being etched in 15 M boiling nitric acid solution for 4 h. However, it was found that prolonging the etching time not only decreases crystallinity but also damages the tubular structure of the CNTs, degrading the hydrogen storage performance. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.