Single-Wall Nanohorns as Electrocatalyst Support for High Temperature PEM Fuel Cells

This work compares the performance of electrodes prepared with electrocatalysts based on platinum supported in single-wall carbon nanohorns (Pt-SWNHs) and in carbon black (Pt-carbon black) for high temperature fuel cells. Membrane electrode assemblies (MEAs) assembled with phosphoric acid doped polybenzimidazole (PBI/H3PO4) membrane were characterized by polarization curves, ac impedance spectroscopy and cyclic voltammetry (CV), at 160 degrees C. A similar power density peak was obtained for both MEAs, at 160 degrees C and 1.0% relative humidity. The electrochemical characterization showed a higher ohmic resistance for the Pt-SWNH compared to carbon black-based MEA, due to the higher hydrophobic character of the SWNH carbon support. Furthermore, the Pt-SWNH anode presented a lower charge transfer resistance than the correspondent carbon black but similar cathode charge transfer resistance. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3551495]