R & D of Novel Anode Catalysts: Suppression of Membrane Degradation, High Activity for H₂ Oxidation, CO-Tolerance, and Robustness Against Air Exposure

Abstract

Platinum skin-covered Pt-M alloy (M=Fe, Co, Ni) nanocatalysts supported on carbon exhibited superlative mass activity for the hydrogen oxidation reaction (HOR) with high CO-tolerance and robustness with respect to air exposure, as novel anode catalysts for the polymer electrolyte fuel cell (PEFC). H₂O₂ is produced when O₂ gas diffuses through the polymer electrolyte membrane (PEM) to the conventional Pt/C hydrogen anode in PEFC. H₂O₂ is the precursor of ・OH radicals, which degrade PEM seriously. It was found for the first time that H₂O₂ production rate at Pt skin-PtCo/C anode during the HOR was suppressed greatly at a practical temperature of 80°C. A remarkably longer lifetime of a PEM with new PtCo/C anode than the case of commercial Pt/C anode has been demonstrated in an accelerated stress test of a single cell. These excellent properties of Pt skin-PtCo have been analyzed multilaterally.