Stable Acidic Water Oxidation with a Cobalt Iron Lead Oxide Catalyst Operating via a Cobalt Selective Self Healing Mechanism

The instability and expense of anodes for water electrolyzers with acidic electrolytes can be overcome through the implementation of a cobalt iron lead oxide electrocatalyst, [Co Fe Pb]Ox, that is self healing in the presence of dissolved metal precursors. However, the latter requirement is pernicious for the membrane and especially the cathode half reaction since Pb2 and Fe3 precursors poison the state of the art platinum H2 evolving catalyst. To address this, we demonstrate the invariably stable operation of [Co Fe Pb]Ox in acidic solutions through a cobalt selective self healing mechanism without the addition of Pb2 and Fe3 and investigate the kinetics of the process. Soft X ray absorption spectroscopy reveals that low concentrations of Co2 in the solution stabilize the catalytically active Co Fe sites. The highly promising performance of this system is showcased by steady water electrooxidation at 80 1 amp; 8201; C and 10 amp; 8197;mA amp; 8201;cm amp; 8722;2, using a flat electrode, at an overpotential of 0.56 0.01 amp; 8197;V on a one week timescal