LAUSR

The elevated toxicity and persistent bioaccumulative propensity of per‐ and polychlorinated organics (PCOs) pose a substantial environmental hazard; however, current dechlorination technologies encounter challenges in surmounting the cumulative reductive inertia inherent to PCOs, resulting in low dechlorination efficiency and the persistence of ecotoxicity. Here, a vacancy‐engineered zero‐valent iron (ZVI) is proposed to address this challenge. The surface‐modified carbon vacancies can extract outward‐flowing electrons from lattice copper‐doped ZVI (CvCu‐ZVI), which react with trapped protons to generate reactive hydrogen in situ that subsequently spills over onto ZVI. Reversible hydrogen spillover enhances electron transfer, and superhydrophobic modification leads to a 38.1‐fold increase in unit site activity and up to 95% electron utilization in CvCu‐ZVI. Excitingly, this approach achieves carbon tetrachloride complete dechlorination, a typical PCOs, with a record intrinsic activity of 13.7 h−1, outperforming state‐of‐the‐art ZVI‐based reductants. Theoretical calculations reveal that modulated hydrogen spillover substantially reduces the dechlorination energy barrier of low‐chlorinated intermediates, facilitating C─Cl bond dissociation. Furthermore, this novel ZVI has a lower production cost and environmental impact, and can be integrated into permeable reaction units for long‐term efficient organohalogen pollution remediation in natural groundwater. This broadly applicable approach establishes a promising paradigm for the sustainable remediation of PCOs pollution.