Influence of Iron Source Type on the Electrocatalytic Activity toward Oxygen Reduction Reaction in Fe-N/C for Al-Air Batteries

Abstract

Iron and nitrogen codoped carbon (Fe-N/C) materials are regarded as promising non-noble metal catalysts in fuel cell and metal air batteries. Iron precursors in synthesis seem to be related to the performance for the resultant catalysts. Herein, the influence of iron source types on the electrocatalytic performance toward ORR was investigated in details. We chose FeCl3 center dot 6H(2)O and ferrocene on behalf of Fe inorganic salts and Fe complexes, respectively, and we synthesized the catalysts via a simple pyrolysis of the mixture of BP2000, dicyandiamide and iron precursor. It is found that free Fe3+ in Fe salts with dicyandiamide can prepare N-doped carbon nanotubes during the pyrolysis process, however, Fe complexes are unable. N-doped carbon nanotubes can promote the ORR performance of the as-prepared Fe-N/C catalyst, because they could function as both the high-efficiency catalytic group via 4-electron (4 e(-)) pathway and the protector of Fe2C@Fe/C active sites. Accordingly, Fe salts with free iron ions are better than Fe complexes when used as iron precursors. (C) The Author(s) 2018. Published by ECS.