Recent Advances of Fe-N-C pyrolyzed catalysts for the oxygen reduction reaction

Abstract This review summarizes recent advances in the development of pyrolyzed M-N-C catalysts for the oxygen reduction reaction, focused on activity, stability, and the reactivity descriptors proposed for the rational design of pyrolyzed M-N-C catalysts. We discuss the last advances in achieving high catalytic activity, stability, and the new insights on the characterization of FeN4 actives sites by Mossbauer spectroscopy in combination with DFT calculations of the Fe-N-C catalysts. In addition, we present the different reactivity descriptors proposed in the literature for the rational design of Fe-N-C pyrolyzed materials: (i) structural descriptors determined by XPS and Mossbauer spectroscopy, and (ii) the redox potential of the active center MNx.