Engineering CoN₄ and FeN₄ Dual Sites with Adjacent Nanoclusters on Flexible Porous Carbon Fibers for Enhanced Electrocatalytic Oxygen Reduction and Evolution

Abstract Dual‐atom catalysts (DACs) possess tunable electronic structures and efficient atom utilization, making them highly promising for catalyzing the oxygen reduction reaction/oxygen evolution reaction (ORR/OER). However, achieving high catalytic activity and stability for both ORR and OER in DACs remains a challenge. Herein, a flexible membrane of porous carbon fiber anchored with atomically scattered CoN₄/FeN₄ dual sites and adjacent Co₂Fe₂/Fe₅ nanoclusters (Co, Fe‐DACs/NCs@PCF) is synthesized. The local geometry and electronic structure of the CoN₄/FeN₄ sites, which act as reaction centers for ORR/OER, are finely regulated by the neighboring Co₂Fe₂/Fe₅ nanoclusters. This unique structure imparts Co, Fe‐DACs/NCs@PCF with exceptional activity and durability toward ORR/OER, outperforming the performance of single‐atom catalysts containing only CoN₄ or FeN₄ sites, as well as commercial Pt/C and RuO₂ catalysts. Zinc–air battery employing a Co, Fe‐DACs/NCs@PCF cathode exhibits outstanding stability, maintaining cyclability for over 1500 h, outperforming a Pt/C + RuO₂ air cathode. Theoretical calculations highlight distinct synergies between Fe₅ (Co₂Fe₂) clusters and FeN₄ (CoN₄) sites, which optimize the coupling strength of Fe(Co)─OH at the potential‐determining steps and thus improve ORR (OER) catalytic kinetics. This study lays a theoretical and practical foundation for rational design of heterostructure catalysts featuring coexisting DACs and nanoclusters within porous carbon fibers.