Oxygen evolution on Co3O4 and Li-doped Co3O4 coated electrodes in an alkaline solution

The oxygen evolution reaction (OER) was investigated at 60 degrees C in 15 wt% NaOH solution on Co3O4, Li-doped Co3O4 and perovskite-type oxide (LaNiO 3) electrodes. Cobalt and Li-doped cobalt oxides were obtained by different preparation techniques and were applied to chemically-pickled nickel plate s. The obtained phases were structurally characterized by X-ray powder diff raction, The electrodes were subjected to electrochemical measurements, bef ore and after electrochemical ageing (21 days, 150 mA cm(-2)). The correlat ion between the coating preparations and their electrocatalytic activity wa s investigated. The efficiency of the studied electrodes seems to depend on the preparation method. Two Tafel slopes for the OER were observed in most cases. This behaviour was interpreted on the basis of a change in the vale nce state of the surface oxide. (C) 1999 International Association for Hydr ogen Energy. Published by Elsevier Science Ltd. All rights reserved.