Fig. 4: PEMFC tests.
From: Iron atom–cluster interactions increase activity and improve durability in Fe–N–C fuel cells
a–c Polarization and power density curves of the indicated catalysts (b, c) before and after the stability test at a constant voltage of 0.5 V under 1 bar H2–air (a). d Polarization curves of FeSA/FeAC−2DNPC (under 1 bar H2–O2) through 30,000 square-wave cycles between 0.6 and 0.95 V under H2–N2. e Polarization and power density curves of FeSA/FeAC−2DNPC under 1 and 2 bar H2–O2. Test conditions: cathode loading 1.5 mgFe–N–C cm−2 and, anode loading 0.2 mgPt cm−2, Nafion 211 membrane, 5 cm2 electrode, 80 °C, 100% relative humidity (RH), flow rates of 300/600 ml min−1 for H2–air polarization, 100/100 ml min−1 for H2–air stability test, and 300/400 ml min−1 for H2–O2 polarization. f Comparison of mass activity of the high-performing Pt-group-metal free catalysts in PEMFC under 1 bar H2–O2. The references to the data points are supplied in Supplementary Table 8. Source data are provided as a Source Data file.
