Breaking the Schottky Barrier by Strain Effect: N‐Doped Zero‐Valent Iron for Dual‐Pathway Synergistic Peroxymonosulfate Activation

Abstract Zero‐valent iron (ZVI) is commonly employed in peroxymonosulfate‐based advanced oxidation processes (PMS‐AOPs). However, the Schottky barrier between the ZVI and the surface iron oxide shell hinders electron transfer. Herein, N‐doped zero‐valent iron composite carbon materials (N‐sZVI@NC) are successfully prepared via a one‐step carbonisation method using metal‐organic frameworks (MOFs) as a precursor. N element doped into Fe lattice induce the tensile strain effect, which raises the Fermi level of ZVI, hence lowering the Schottky barrier. The reduction in the Schottky barrier allows more electrons to activate PMS, generating ·SO ₄ ⁻ and ·OH radicals. Concurrently, sp ² ‐conjugated carbon materials with strong electron‐transfer capabilities facilitate the electron‐transfer degradation process. The N‐sZVI@NC/PMS system achieves dual‐pathway synergistic oxidation via co‐capture of electron‐rich pollutants and PMS, demonstrating exceptional efficiency in the degradation of persistent organic pollutants. The kinetic constants and PMS utilization rates are up to 0.15 min ⁻¹ and 48.4%, respectively, which are 7.5 and 3.1 times higher than those of the nZVI@C without N doping. N‐sZVI@NC‐2 exhibits excellent stability, with over 90% degradation efficiency throughout 10 cycles of continuous‐flow reaction experiments, and demonstrates outstanding practical capabilities for treating soil and industrial wastewater. Overall, this study provides new insights into the development of ZVI composites with high activity and stability.