Breaking the Linear Scaling Relationship: Bioinspired Electronic Coupling in S‐Bridged Fe−Fe Dual Sites for Efficient Oxygen Reduction

ABSTRACT

Dual‐atom catalysts (DACs) provide a promising approach to overcome the linear scaling relationship that limits the activity of single‐atom catalysts for oxygen reduction reactions (ORR). However, the lack of a direct electronic bridge between the two sites, along with the inherently localized character of transition‐metal 3d orbitals, often hinders coherent electronic regulation and efficient orbital overlap with reaction intermediates. Herein, inspired by the natural iron‐sulfur clusters, we design an S‐bridged Fe−Fe DAC (Fe ₂ N ₆ ‐S/SNC). The sulfur bridge acts as an intrinsic charge‐transfer channel, enabling strong electronic coupling between the Fe centers. Combined experimental and theoretical analyses demonstrate that this configuration promotes dynamic charge redistribution and enhances Fe 3d‐S 2p orbital hybridization, which cooperatively optimizes oxygen intermediate adsorption and enhances the ORR kinetics. Consequently, Fe ₂ N ₆ ‐S/SNC exhibits outstanding alkaline ORR performance with a half‐wave potential of 0.93 V, a kinetic current of 35.40 A g ⁻¹ , and a high turnover frequency of 2.49 e ⁻ site ⁻¹ s ⁻¹ . When integrated into an ampere‐hour‐scale zinc‐air battery, it delivers a discharge capacity of 4.76 Ah and a peak power of 2.67 W. This work demonstrates a bio‐inspired bridging strategy to create electronically coherent dual‐atom sites, offering fresh perspectives on the rational design of high‐performance DACs for energy conversion devices.