Nickel-cobalt oxide-coated electrodes: influence of the preparation technique on oxygen evolution reaction (OER) in an alkaline solution

The oxygen evolution reaction (OER) was investigated at 60 degrees C in 15 wt% NaOH solution on NiCo2O4 electrodes. Nickel-cobalt oxides were obtained by different preparation techniques and they were applied to chemically pickled nickel plates. Fresh and artificially aged electrodes were subjected to electrochemical tests. The ageing was performed for 21 days. The correlation between the coating preparations and their electrochemical performances was investigated by analysis of the electrochemical data. The efficiency of the NiCo2O4 electrodes changed significantly with the changing of 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 oxide. The kinetic parameters obtained on NiCo2O4 electrodes were compared and discussed according to the preparation methods. (C) 1999 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.