Fig. 5.

a ORR polarization plots of as-prepared samples (rotation rate: 1600 rpm) in 0.1 M KOH at a scan rate of 5 mV s⁻¹. b OER polarization plots (second OER scan) of as-prepared samples in 1.0 M KOH at a scan rate of 5 mV s⁻¹. c ORR polarization plots of as-prepared samples (rotation rate: 1600 rpm) after the OER process in 0.1 M KOH at a scan rate of 5 mV s⁻¹. d Schematic of a catalyst-loaded electrode in contact with the liquid electrolyte, and the corresponding simulated equivalent circuit. e Electrochemical impedance spectra (EIS) at a three-electrode system. f Bode plots of EIS spectra. Fe/Co-CTs/NC (named 1), Fe/Co-CTs/CNTs (named 2), Fe/Co-NPs/NC (named 3), and * denote the corresponding sample after the first OER process. The capacitive current of g Fe/Co-CTs/NC and h) Fe/Co-CTs/CNTs measured at 1.15 V versus RHE as a function of scan rate. i–k Galvanostatic discharge and charge cycling stability of i Fe/Co-CTs/NC and j, k Fe/Co-CTs/CNTs. Electrolyte: 6.0 M KOH with 0.2 M zinc acetate