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

Abstract 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 Co II ‐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 ( E onset : 0.97 V) and half‐wave potential ( E 1/2 : 0.86 V) comparable to that of commercial Pt/C ( E onset =1.02 V; E 1/2 =0.88 V), which outperforms the corresponding Co‐N‐C‐900 sample ( E onset =0.92 V; E 1/2 =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 Co II ‐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.