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 (LaNiO3) electrodes. Cobalt and Li-doped cobalt oxides were obtained by different preparation techniques and were applied to chemically-pickled nickel plates. The obtained phases were structurally characterized by X-ray powder diffraction, The electrodes were subjected to electrochemical measurements, before and after electrochemical ageing (21 days, 150 mA cm(-2)). The correlation between the coating preparations and their electrocatalytic activity was 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 valence state of the surface oxide. (C) 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.