Fig. 4: Electrochemical tests of CuNa-CF and other reference catalysts.
a Oxygen reduction reaction polarization curves without iR correction for CuNa-CF, CuPc+NaCl-CF, CuPc-CF, NaCl-CF, CF, and commercial 20% Pt/C catalysts in O2-saturated 0.1 M KOH solution at 1600 rpm with a scan rate of 5 mV s−1 (the resistance of the solution was 40 ± 5 Ω). b Comparison of onset potential (Eonset), half-wave potential (E1/2), and kinetic current density (Jk, at 0.85 V, V versus RHE) for different catalysts. c Linear sweep voltammetry (LSV) curves of the CuNa-CF catalyst at different rotation speeds (400, 625, 900, 1225, and 1600 rpm). d Koutecky-Levich plots and corresponding electron transfer numbers for the CuNa-CF catalyst at different potentials (0.2 V, 0.3 V, 0.4 V, 0.5 V, 0.6 V, and 0.7 V, V versus RHE). e H2O2 yield and electron transfer number of the CuNa-CF catalyst and Pt/C catalyst measured by the rotating ring-disk electrode (RRDE). f Long-term electrochemical stability of the CuNa-CF catalyst and Pt/C catalyst.
