Kramm, U.; Zana, A.; Vosch, T.; Fiechter, S.; Arenz, M.; Schmeißer, D.: On the structural composition and stability of Fe–N–C catalysts prepared by an intermediate acid leaching. Journal of Solid State Electrochemistry 20 (2016), p. 969-981

The development of highly active and stable non-noble metal catalysts (NNMC) for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEM-FC) becomes of importance in order to enable cost reduction. In this work, we discuss the structural composition as derived from Fe-57 Mößbauer spectroscopy and X-ray dif- fraction, catalytic performance determined by a rotating (ring) disk electrode (RRDE) technique and stability evaluation of our Fe–N–C catalysts prepared by an intermediate acid leaching (IAL). The advantage of this IAL is given by a high density of active sites within the catalyst, as even without sulphur addition, an iron carbide formation and related disintegration of active sites are inhibited. In addition, our accelerated stress tests illustrate better stability of the sulphur-free IAL catalyst in comparison to the sulphur-added one.