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. 2018 Jun 11;115(26):6626–6631. doi: 10.1073/pnas.1800771115

Fig. 3.

Fig. 3.

Characterizations of ORR activity in acidic medium. (A) RRDE ORR polarization curves of as-synthesized catalysts in O2-saturated 0.5 M H2SO4 and 20% Pt/C in 0.1 M HClO4 with a sweep rate of 5 mV/s. (B) Tafel plots derived from SA-Fe/NG, Fe/NG, and 20% Pt/C in acidic conditions. (C) The percentage proportion of peroxide to the total oxygen reduction products of SA-Fe/NG, Fe/NG, and 20% Pt/C at different potentials (0.2–0.6 V) in O2-saturated acidic solutions from RRDE. (D) LSV curves of SA-Fe/NG and before and after 5,000 potential cycles in O2-saturated 0.5 M H2SO4. (E) Methanol resistance of SA-Fe/NG in O2-saturated 0.5 M H2SO4 without and with CH3OH. (F) Polarization and power density curves of the SA-Fe/NG-based and 20% Pt/C-based membrane electrode assemblies in PEMFCs. Test conditions: cathode loading 2.0 mg cm−2 for SA-Fe/NG and 0.2 mg Pt cm−2 for 20% Pt/C, anode loading 0.2 mg Pt cm−2, Nafion 211 membrane, 5-cm2 electrode area, 80 °C, 100% relative humidity, 2.5-bar O2/H2.