The effect of N precursors in Fe-N/C type catalysts based on activated silicon carbide derived carbon for oxygen reduction activity at various pH values

Abstract

Simple and modified synthesis route for preparation of Fe-N/C type oxygen reduction reaction (ORR) catalysts has been worked out and discussed. The significant effect of the N precursor chemical composition on the ORR activity in 0.1 M KOH and 0.1 M HClO4 electrolyte solutions has been demonstrated. The half-wave potential values increased in the following order: C(SiC) < Fe + Urea/C < Fe + EDTA/C < Fe + DIPO/C ≤ Fe + Phen/C ≤ Fe + Bipyr/C in both electrolyte solutions studied. Molar ratio of Fe:N precursor and Fe content change in the Fe + Bipyr/C catalyst was found to be negligible. Noticeable change in ORR activity has been observed after acid treatment step of Fe + Bipyr/C. The 150-h durability tests demonstrated that in terms of the activity/stability ratio the Fe + Phen/C is the best ORR catalyst.