Fe-N-carbon black for the oxygen reduction reaction in sulfuric acid

A Fe-N-C catalyst was prepared by pyrolyzing carbon black supported Fe-imidazole complexes. The effect of different pyrolysis temperatures on the catalysts' oxygen reduction reaction (ORR) activity was investigated by electrochemical rotating disk electrode tests in 0.5 M H2SO4. The Fe-N-C catalyst heat-treated at 700 °C was found to display the best ORR activity with a highest half-wave potential of 0.656 V vs. normal hydrogen electrode (NHE), which was only 64 mV lower than that of the commercial Pt-C (loading: 10 μgPt cm−2), and a lowest H2O2 yield (0.6% at 0.4 V vs. NHE). Furthermore, potential cycling tests showed that the catalyst had a better electrochemical stability than Pt-C catalyst. X-ray photoelectron spectroscopy characterization of these catalysts was also conducted to identify the active nitrogen species for ORR.