Hindawi Publishing Corporation Advances in Physical Chemistry Volume 2011, Article ID 679246, 10 pages doi:10.1155/2011/679246 Research Article Sequential Electrodeposition of Platinum-Ruthenium at Boron-Doped Diamond Electrodes for Methanol Oxidation Ileana Gonz ´ alez-Gonz ´ alez, 1, 2 Camille Lorenzo-Medrano, 1, 2 and Carlos R. Cabrera 1, 2 1 Department of Chemistry, University of Puerto Rico, R´ ıo Piedras Campus, P.O. Box 70377, San Juan, PR 00936-8377, USA 2 Center for Advanced Nanoscale Materials, University of Puerto Rico, R´ ıo Piedras Campus, P.O. Box 70377, San Juan, PR 00936-8377, USA Correspondence should be addressed to Carlos R. Cabrera, carlos.cabrera2@upr.edu Received 5 April 2011; Revised 11 July 2011; Accepted 18 July 2011 Academic Editor: Milan M. Jaksic Copyright © 2011 Ileana Gonz´ alez-Gonz´ alez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Sequential electrodeposition of Pt and Ru on boron-doped diamond (BDD) films, in 0.5 M H 2 SO 4 by cyclic voltammetry, has been prepared. The potential cycling, in the aqueous solutions of the respective metals, was between 0.00 and 1.00 V versus Ag/AgCl. The catalyst composites, Pt and PtRu, deposited on BDD film substrates, were tested for methanol oxidation. The modified diamond surfaces were also characterized by scanning electron microscopy-X-ray fluorescence-energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The scanning Auger electron spectroscopy mapping showed the ruthenium signal only in areas where platinum was electrodeposited. Ruthenium does not deposit on the oxidized diamond surface of the boron-doped diamond. Particles with 5–10% of ruthenium with respect to platinum exhibited better performance for methanol oxidation in terms of methanol oxidation peak current and chronoamperometric current stability. The electrogenerated • OH radicals on BDD may interact with Pt surface, participating in the methanol oxidation as shown in oxidation current and the shift in the peak position. The conductive diamond surface is a good candidate as the support for the platinum electrocatalyst, because it ensures catalytic activity, which compares with the used carbon, and higher stability under severe anodic and cathodic conditions. 1. Introduction The direct methanol fuel cells (DMFC) are electrochemical cells that convert chemical energy in electrical energy that can be use to power all kind of appliances. Similar to polymer electrolyte membrane fuel cells (PEMFCs), in the DMFC the anode catalyst draws the hydrogen from the methanol, and both systems use a solid electrolyte, reducing the corrosion of the device and improving the power density. Various catalytic composite systems have been studied, including PtRuOsIr [1], PtRuOs [2], PtMo [3, 4], and PtRu [5, 6]. Electrodes with catalyst nanoparticles have been found to have highly catalytic performance, and the catalytic activity was found to depend on the particle size, the nature of the support, as well the preparation method [7]. One of the subjects of research on high-efficiency fuel cells is how to minimize the electrocatalytic noble metal load- ing without losing the high catalytic activity. This is achieved by dispersing nanoparticles of the catalytic materials (mainly Pt-based alloys) on high surface area materials used as supports. The supports need to, in addition to having high surface, be stable and conductive. The most commonly used particle support is carbon blacks, these undergo irreversible oxidation at positive potentials, and this is a challenge particularly on the oxygen reduction electrode where they undergo high positive potentials (0.7–1.0 versus NHE), but it can occur in the anode during fuel starvation [8–10]. When the carbon blacks support oxidizes their resistance increase, the electrocatalytic particles become loose, and they lose a high number of reaction sites due to agglomeration [10–14]. The development of advanced support materials that are stable at high potentials, low pH, and relatively elevated temperatures is still the subject of much study [15]. Diamond, carbon nanotubes [16], nanoporous supports and highly ordered carbon materials have been studied in order to improve the stability of the electrodes of the cell.