Durability of different carbon nanomaterial supports with PtRu catalyst in a direct methanol fuel cell Annukka Santasalo-Aarnio a , Maryam Borghei b , Ilya V. Anoshkin b , Albert G. Nasibulin b , Esko I. Kauppinen b , Virginia Ruiz b,c , Tanja Kallio a, * a Research Group of Fuel Cells, Department of Chemistry, Aalto University, P.O. Box 16100, 00076 Aalto, Finland b Nanomaterials Group, Department of Applied Physics, Aalto University, P.O. Box 16100, 00076 Aalto, Finland c CIDETEC-IK4 (Centre for Electrochemical Technologies), Paseo Miramo ´n 196, 20009 Donostia-San Sebastia ´n, Spain article info Article history: Received 4 July 2011 Received in revised form 11 October 2011 Accepted 1 November 2011 Available online 9 December 2011 Keywords: Carbon nanotubes Carbon nanofibers Methanol oxidation Direct methanol fuel cell (DMFC) abstract PtRu catalysts with similar particle size and composition were deposited on three different carbon supports: Vulcan, graphitized carbon nanofibers (GNF) and few-walled carbon nanotubes (FWCNT) and their performance for methanol oxidation was studied in an electrochemical cell and in a single cell DMFC. The electrochemical results indicate that with PtRu/GNF and PtRu/FWCNT higher current densities are obtained and oxidation intermediates deactivate the surface less compared to the same catalyst on Vulcan support. Conversely, PtRu/Vulcan provided the highest open circuit voltage OCV and current densities in DMFC experiments due to a well-optimized electrode layer structure. Because stability is a key requirement for fuel cell commercialization, 6-day-long fuel cell stability tests were carried out, showing that PtRu/Vulcan degraded significantly. This was due to the collapse of the secondary structure of the electrode layer revealed by post characterization of the membrane electrode assembly (MEA) with SEM and TEM. PtRu/GNF exhibited slightly poorer initial performance but better stability because the structure of the anode layer was maintained. PtRu/FWCNT showed the worst initial performance and long-term stability. The good stability of non-optimized PtRu/GNF MEAs shows the potential of these novel nanocarbon supported catalysts as stable fuel cell components after proper MEA optimization. Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. 1. Introduction Fuel cells running on liquid fuels such as direct methanol fuel cells (DMFCs) are very promising energy sources for low power electronic applications but improvements in performance and design, as well as cost reduction are still necessary [1]. In particular, developing more efficient and durable electro- catalysts for methanol oxidation is crucial for achieving enhanced performance and increasing the lifetime of DMFCs. With the aim of reducing costs associated with the precious metal, nanosized mono and bimetallic catalysts deposited on conducting carbons with high surface area are typically used. Along with the nature of the catalysts, the search for better and more stable anode material has comprised evaluating the influence of the carbon support on the catalytic activity. A good catalyst support should have high surface area and conductivity, exhibit good permeability to reactants and have electrochemical stability under fuel cell operating conditions. * Corresponding author. Tel.: þ358 9470 22583; fax: þ358 9470 22580. E-mail address: tanja.kallio@tkk.fi (T. Kallio). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he international journal of hydrogen energy 37 (2012) 3415 e3424 0360-3199/$ e see front matter Copyright ª 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhydene.2011.11.009