Degradation study of Pt-based alloy catalysts for the oxygen reduction reaction in proton exchange membrane fuel cells

Investigations of the durability of Pt/C, PtCo/C and PtFe/C catalysts for applications on the cathode of proton exchange membrane fuel cells (PEMFC) are carried out using an accelerated degradation procedure (ADP). Electronic and structural properties of the catalysts before and after the ADP are obtained by energy dispersive X-ray spectrometry, X-ray diffraction and X-ray absorption spectroscopy. The electrochemically active Pt surface area of the electrodes is estimated by cyclic voltammetry, while the electrochemical performance is evaluated via polarization measurements at a test station, for single cells fed with H2/air at 70 °C, prior to and in the course of the ADP. Results show a decrease in the fuel cell performance in the course of the ADP. A decrease in the kinetics of the oxygen reduction reaction is in agreement with a loss of electrochemical active Pt surface area on the catalysts, as verified by cyclic voltammetry and X-ray diffraction.