Multiwalled carbon nanotubes (MWCNTs), with typical lengths of 20 mum and diameters of 40 nm, have been grown directly on carbon paper backing. A sulfonic acid-silicate intermediate was used to deposit Pt particles on the MWCNTs in order to obtain an electrode that could be used in electrocatalysis. The electrical path between the Pt nanoparticles (1.2 +/- 0.3 nm in size) and the carbon paper, through the MWCNTs, was demonstrated by cyclic voltammetry. The Pt surface density of a typical MWCNT composite electrode is estimated to be about 25% of that of an ELAT electrode from E-TEK, containing 0.4 mg Pt/cm(2). (C) 2003 Elsevier B.V. All rights reserved.