Spin‐Regulated Fe‐Cu Diatomic Catalytic Chemistry Enables Significant Minimization of Catalyst Consumption With High‐Efficiency Fenton‐Like Activity

ABSTRACT The high cost and limited metal loading of single‐atom catalysts hinder their broader applications in Fenton‐like reaction for water treatment. Herein, we developed an Fe‐Cu diatomic catalyst supported on N‐doped carbon (Fe‐Cu‐CN) that enabled catalyst minimization while maintaining high peroxymonosulfate (PMS) activation efficiency. By tailoring asymmetric Fe‐Cu coordination and inducing a spin‐state transition of Fe from low‐spin to high‐spin, the catalyst enhanced Fe 3d ‐O 2p electron coupling and substantially improved intrinsic activity. The Fe‐Cu‐CN/PMS system enabled a highly efficient electron transfer pathway for pollutant degradation, achieving rapid bisphenol A removal (100% within 5 min; k obs = 1.61 min − 1 ) with only 10%–20% of the catalyst dosage commonly reported in the literature. Density functional theory calculations and electrochemical analyses revealed that heteronuclear coordination modified the spin‐state of the active center, narrowing the gap between the d‐band center of Fe 3d orbitals and the Fermi energy level to strengthen the electronic interaction at the reaction interface, resulting in a lower free energy barrier of PMS adsorption thermodynamically. Furthermore, the life‐cycle analysis demonstrated superior environmental performance. This study provides a generalizable strategy to enhance unit catalytic activity through spin‐state engineering, offering practical potential for PMS‐based water treatment.