Strategic secondary coordination implantation towards efficient and stable Fe‐N‐C electrocatalysts for PEMFCs

While state‐of‐the‐art Fe‐N‐C catalysts demonstrate platinum‐comparable initial activity for the oxygen reduction reaction (ORR), their operational durability in proton exchange membrane fuel cells (PEMFCs) remains fundamentally limited by progressive destabilization of Fe‐N bond under electrochemical cycling, resulting in irreversible metal leaching, catastrophic catalyst degradation and the so‐called activity‐stability trade‐off. Herein, guided by first‐principles screening, we demonstrate that the strategic implantation of transition metal ions with d‐orbital characteristics analogous to the active site into the secondary coordination sphere, functioning as non‐catalytic stabilizers, enables dynamic neutralization of reaction intermediates‐induced electronic polarization, thereby achieving stabilization of metal‐nitrogen bonds during the ORR cycle. As a proof‐of‐concept, the integration of isovalent Ru ions as electron‐buffing site in the designed FeRu dual‐atom catalyst not only achieves a high peak power density of 1.73 W cm‐2 with a current density of 58 mA cm‐2 at 0.9 V, but also exhibits exceptional durability, with a current decay rate of just 0.2 mA cm‐2 h‐1 and over 97% Fe retention after prolonged stability tests. This stands in stark contrast to Fe‐N‐C counterparts, which retain less than 11% of Fe sites under identical conditions.