Geometry-Controlled Cooperativity at Binuclear Fe₂-N₆ Sites Enables Selective Fe^IV═OGeneration for Durable...

Single atom catalysts (SACs) are emerging as a promising platform for Fenton-like water purification; however, their practical deployment is often constrained by the trade-off between high intrinsic activity and long-term stability. Here, we construct an N-bridged binuclear architecture that pairs isolated Fe-N₄ sites into a precisely defined Fe₂─N₆ configuration on N-doped carbon (Fe₂─N₆/NC). This Fe─N─Fe architecture induces charge delocalization and regional polarization, strengthening interfacial electronic coupling and enabling cooperative dual-site adsorption of peroxymonosulfate (PMS). As a result, PMS activation becomes thermodynamically favored and proceeds selectively via a high-valent Fe^IV═O pathway, fundamentally distinct from the singlet-oxygen-dominated regime of conventional single-atom sites (Fe─N₄). The Fe^IV═O species generated over the proximity dual site simultaneously accelerate pollutant degradation while suppressing demetalation, thereby securing both catalytic activity and operational durability. In the continuous-flow reactor, Fe₂─N₆/NC maintains stable performance over 14 days of operation. Life cycle assessment and real-world hospital wastewater treatment further demonstrate concurrent organic removal, reduced toxicity, and lower environmental impact. This work proposes binuclear site engineering as a general strategy to overcome the catalytic activity-stability dilemma in SAC-based Fenton-like systems, advancing their translation toward scalable, sustainable systems for real-world water purification.