Rational Synthesis of Iron/Nitrogen‐Doped Carbon Catalyst through a Spatial Isolation Strategy for Efficient Oxygen Reduction in Acidic and Alkaline Media

Abstract It remains challenging to rationally synthesize iron/nitrogen‐doped carbon (Fe/N‐C) catalysts with rich Fe−N x atomic active sites for improved oxygen reduction reaction (ORR) electrocatalysis. A highly efficient Fe/N‐C catalyst, which has been synthesized through a spatial isolation strategy, is reported. Derived from bioinspired polydopamine (PDA)‐based hybrid microsphere precursors, it is a multifunctional carrier that loads atomically dispersed Fe 3+ /Zn 2+ ions through coordination interactions and N‐rich melamine through electrostatic attraction and covalent bonding. The Zn 2+ ions and melamine in the precursor efficiently isolate Fe 3+ atoms upon pyrolysis to form rich Fe−N x atomic active sites, and generate abundant micropores during high‐temperature treatment; as a consequence, the resultant Fe‐N/C catalyst contains rich catalytically active Fe−N x sites and a hierarchical porous structure. The catalyst exhibits improved ORR activity that is superior to and close to that of Pt/C in alkaline and acidic solutions, respectively.