Vertically aligned carbon nanotubes (VACNTs) grown on carbon paper were obtained by the spray pyrolysis method and highly dispersed Pd nanoparticles were deposited on VACNTs by the wet chemical method. For comparison, the entangled carbon nanotubes (ECNTs) and Vulcan XC-72 based electrodes were fabricated by brush painting the corresponding Pd/ECNTs and Pd/XC-72 catalysts on carbon paper, respectively. Compared with Pd deposition on the entangled carbon nanotubes (ECNTs) and Vulcan XC-72 electrodes, the VACNTs electrode exhibited higher activity for formic acid oxidation, which is mainly due to the three-dimensional structure and better conductive paths in the VACNTs electrode, as well as higher Pd utilization. (c) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.