Fig. 3: Electrocatalytic performance of Fe-N-C and Fe-N-CCVM in three-electrode setup.

a Cyclic voltammetry curves of Fe-N-C and Fe-N-CCVM in N2 saturated 0.1 M HClO4 with a sweep rate at 10 mV/s. b ORR polarization curves of Fe-N-C and Fe-N-CCVM in O2 saturated 0.1 M HClO4 with a sweep rate at 10 mV/s. ORR polarization curves. (c) Fe-N-CCVM and (d) Fe-N-C before and after different potential cycles between 0.6 and 1.0 V in O2 saturated 0.1 M HClO4 with a sweep rate at 10 mV/s. e electron transfer number and (f) H2O2 yield of Fe-N-C and Fe-N-CCVM.