Fig. 4

(a) CV curves of CoNC@NCXS-800 in 0.1Â M KOH saturated with N2 and O2; (b) ORR polarization curves of the electrocatalyst in 0.1Â M KOH solution; (c) Corresponding Tafel effect plots; (d) LSV curves of CoNC@NCXS-800 at different rotational speeds; (e) RRDE measurements corresponding to disc and ring currents (inset) and peroxide yield (H2O2%) and electron transfer number (n) of CoNC@NCXS-800 calculated from RRDE measurements; (f) ORR polarization curves of CoNC@NCXS-800 before and after 1000 CV cycles test; (g) OER polarization curves; (h) Corresponding Tafel effect plots; (i) Bifunctional catalytic activity of the electrocatalysts for ORR and OER.