Interfacial Bonding Engineering Enables Built‐In Electric Field for Sustained and Controllable Peroxide Activation

Achieving durable activation of peroxides with regulated reactive oxygen species (ROS) generation remains a critical challenge for advanced oxidation processes under harsh oxidative conditions. Herein, we design an interface‐engineered heterostructure by firmly anchoring FeS 2 nanoparticles onto reduced graphene oxide (rGO) via robust Fe─S─C bonding, which creates a strong built‐in internal electric field (BIEF) of ∼32 kV/cm. This BIEF drives directional electron transfer from electron‐rich sulfur sites to Fe 3+ , thereby accelerating Fe 2+ regeneration and sustaining peroxymonosulfate (PMS) activation. The FeS 2 /rGO + PMS system achieves high organic degradation performance (>90% removal over 25 h) at a low initial PMS dosage of 1.0 g/L. Mechanistic studies reveal that the BIEF not only enhances the intrinsic activity of iron sites but also selectively regulates the formation of both radical (SO 4 •− , HO • ) and non‐radical ( 1 O 2 ) pathways. This work illustrates BIEF engineering as a versatile materials design strategy toward durable, efficient, and ROS‐regulated oxidation catalysts for sustainable environmental remediation.