Fig. 7. Electrochemical oxygen reduction on as-prepared CoOx samples. (a) LSV curves of CoO, CoOx-400, CoOx-600 and CoOx-800 samples with a sweep rate of 5 mV s−1 at 1600 rpm; (b) LSV curves of CoOx-800 electrode at a scan rate of 5 mV s−1 under various rotation rates; (c) corresponding Koutecky–Levich plots of CoOx-800 electrode; (d) CV curves of CoOx-800 electrodes with (red curve) and without (black curve) adding 3 M methanol into the O2-saturated 0.1 M KOH electrolyte.
