Fig. 4.
a ORR polarization plots of as-prepared samples (rotation rate: 1600 rpm) in O2-saturated 0.1 M HClO4 at a scan rate of 5 mV s−1. b Percentages of H2O2 produced and the electron transfer numbers of Fe/Co-CTs/NC and Pt/C catalysts. c Chronoamperometric responses of Fe/Co-CTs/NC at 0.7 V in an O2-saturated 0.1 M HClO4 solution. d Electrochemical impedance spectra (EIS) at an open-circuit voltage (OCV) of H2/O2 fuel cell measured at 80 °C using the as-prepared Fe/Co-CTs/NC. e The electrochemical performance (I-V curves) of the H2/O2 fuel cell was measured at 80 °C and 1.0 bar back pressure