OXYGEN EVOLUTION ON ELECTROCHEMICALLY GENERATED COBALT SPINEL COATING

The oxygen evolution reaction (OER) has been investigated in 40wt% KOH at 80 degrees C on a thick cobalt oxide coating obtained by potential cycling of a cobalt electrode for 0, 2, 4, 10 and 17 h in the same el ectrolyte with and without dissolved strontium. The kinetic parameters of the OER were determined after preanodization for 1 h at 1 A cm(-2) . Improved electrocatalytic activity for the OER, better mechanical st rength of the coating and lower variation of the oxygen overpotential with time were noticed up to 70 h of polarization as the coating built up in the presence of dissolved strontium in the electrolyte. The ben eficial effect of dissolved strontium on the electrocatalytic activity is ascribed to the accumulation of Co3O4, which results in a lower Ta fel slope for the OER.