Asymmetric Fe-Te Pairs Enhance Peroxymonosulfate Activation via Surface-Bound Hydroxyl Radicals Pathways

Controlling peroxymonosulfate (PMS) activation at the atomic scale is crucial for steering reactive oxygen species (ROS) pathways, yet design principles that selectively bias PMS chemistry toward interfacial radical states remain elusive. Herein, we report an asymmetric Fe-Te dual-atom pair (FeTe DAs/NC), in which a p-block metalloid electronically modulates an Fe center through pronounced p-d hybridization. This atomic asymmetry reconstructs the local electronic structure, strengthens PMS binding, and directs PMS activation toward the generation and retention of surface-bound hydroxyl radicals. Mechanistic studies reveal surface-bound hydroxyl radicals (^•OH) as the dominant ROS, while singlet oxygen (¹O₂) plays a secondary role. As a result, FeTe DAs/NC achieves complete degradation of carbamazepine within 60 min, markedly outperforming Fe or Te single-atom analogs, together with excellent reactivity and cycling stability across different water matrices and pollutant systems. This work establishes atomic-scale asymmetry and metal-metalloid p-d coupling as an effective strategy for steering PMS activation chemistry toward long-lived interfacial radical states.