Fig. 4
ORR performances of the prepared catalysts and their comparisons in 1 M KOH solution. a CV curves of MnO-T catalysts. b LSV curves of MnO-T catalysts at a scan rate of 10 mV/s. c Stability measurements for MnO-600 sample at the initial cycle and after 2000, 4000 and 6000 cycles. d Time-dependent current density curve at 0.7 V (vs. RHE) obtained by continuous test for 25,000 s. e H2O2 yields of MnO-600 at varied potentials and the corresponding electron transfer numbers. f H2O2 yields (dots) and the corresponding electron transfer numbers (columns) at 0.8 V (vs. RHE) for different catalysts. g Nyquist plots of the catalysts (inset: AC impedance curves of different catalysts at the potential of 0.965 V (vs. RHE) and in the frequency range from 10−2 to 105 Hz). h Tolerance measurements to methanol at 0.7 V (vs. RHE) for Pt/C and MnO-600 catalysts. i Comparison of ORR performances among MnOx-based electrocatalysts in the alkaline electrolyte