Gold autodeactivation during oxygen electroreduction studied by electrochemical impedance spectroscopy

The deactivation of a polycrystalline gold electrode is observed during oxygen electroreduction reaction (ORR) in basic medium. At that, the cause of the process is chemical decomposition of the ORR intermediate and blocking of active sites of the electrode surface by hydroxyl radical-like species. The deactivation mechanism is discussed.

► Gold autodeactivation during oxygen electroreduction reaction.
► Strong hydroxyl radical-like species adsorption.
► Superoxide radical-like species formation on p-Au.
► Impedance data analysis and model calculations.