Enhanced Electron‐Capturing by Single‐Atomic Iron on Pyridinic N‐Deficient Carbon Drives Self‐Oxidative Degradation of Pollutants

Catalysts capable of degrading pollutants without external oxidants are pivotal for sustainable environmental remediation. In this study, iron single atoms anchored on N‐doped carbon with pyridinic nitrogen vacancies (Fe‐SAs/N V ‐C) are synthesized for external oxidant‐free pollutant degradation. The optimized Fe‐SAs/N V ‐C catalyst achieves complete removal of ciprofloxacin (CIP) within 1 min, significantly outperforming N‐doped carbon (with only 70% removal) and attains a total organic carbon mineralization ratio of 75.6% within 15 min. The catalyst maintains excellent activity in high‐salinity solution (500 m M NaCl) and under continuous‐flow operation. Kelvin probe force microscopy measurements confirm a shift in surface potential from 25 to −70 mV. Theoretical calculations reveal that pyridinic N V render the Fe SAs and adjacent C sites more electron‐deficient. These features enable the Fe‐SAs/N V ‐C to efficiently extract electrons from CIP, thereby initiating its self‐oxidation. Concurrently, dissolved oxygen accepts electrons from electron‐rich sites on both the catalyst and CIP, generating singlet oxygen that further promotes the degradation. This work provides new insights into the oxidant‐free degradation mechanism mediated by the synergy of electron‐deficient and electron‐rich sites.