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 CoN 4 /FeN 4 dual sites and adjacent Co 2 Fe 2 /Fe 5 nanoclusters (Co, Fe‐DACs/NCs@PCF) is synthesized. The local geometry and electronic structure of the CoN 4 /FeN 4 sites, which act as reaction centers for ORR/OER, are finely regulated by the neighboring Co 2 Fe 2 /Fe 5 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 CoN 4 or FeN 4 sites, as well as commercial Pt/C and RuO 2 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 + RuO 2 air cathode. Theoretical calculations highlight distinct synergies between Fe 5 (Co 2 Fe 2 ) clusters and FeN 4 (CoN 4 ) 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.