Efficient Fe‐Co‐N‐C Electrocatalyst Towards Oxygen Reduction Derived from a Cationic CoII‐based Metal–Organic Framework Modified by Anion‐Exchange with Potassium Ferricyanide

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Fe‐Co‐N‐C electrocatalysts have proven superior to their counterparts (e.g. Fe‐N‐C or Co‐N‐C) for the oxygen reduction reaction (ORR). Herein, we report on a unique strategy to prepare Fe‐Co‐N‐C−x (x refers to the pyrolysis temperature) electrocatalysts which involves anion‐exchange of [Fe(CN)6]3− into a cationic CoII‐based metal‐organic framework precursor prior to heat treatment. Fe‐Co‐N‐C‐900 exhibits an optimal ORR catalytic performance in an alkaline electrolyte with an onset potential (Eonset: 0.97 V) and half‐wave potential (E1/2: 0.86 V) comparable to that of commercial Pt/C (Eonset=1.02 V; E1/2=0.88 V), which outperforms the corresponding Co‐N‐C‐900 sample (Eonset=0.92 V; E1/2=0.84 V) derived from the same MOF precursor without anion‐exchange modification. This is the first example of Fe‐Co‐N‐C electrocatalysts fabricated from a cationic CoII‐based MOF precursor that dopes the Fe element via anion‐exchange, and our current work provides a new entrance towards MOF‐derived transition‐metal (e.g. Fe or Co) and nitrogen‐codoped carbon electrocatalysts with excellent ORR activity.