Electrochemical investigation of electrocatalysts for the oxygen evolution reaction in PEM water electrolyzers

To develop the proton exchange membrane water electrolyzer (PEMWE) with satisfactory performance and durability for application in a regenerative fuel cell (RFC) system, anode electrocatalysts of Ir, Ru and their oxides were prepared and incorporated into the catalyst coated membranes (CCM) of the PEMWE. Repetitive cyclic voltammetry of the Nafion bonded electrodes, steady state polarization curves and stability testing of the single PEMWE cells were performed to investigate the performance and stability of these electrocatalysts. The structure and specific surface areas of the electrocatalysts were characterized by XRD and BET. IrO2 exhibited a slightly lower performance but a markedly higher stability than the other electrocatalysts. By modifying the preparation process via a colloidal iridium hydroxide hydrate precursor, which permitted a lower heat treatment temperature, its performance was enhanced, corresponding to a terminal voltage of 1.63 V at 1 A/cm2.