Delocalized electron‐enhanced photo‐regeneration based on nanosheet g‐C ₃ N ₄ enables reusable electrochemical antibiotic sensing

Abstract Surface contamination caused by oxidation by‐products severely compromises the signal stability and reusability of electrochemical sensors. However, achieving rapid and complete regeneration of electrode activity under mild conditions remains a challenge. Herein, we develop a delocalized‐electron‐driven photocatalytic regeneration strategy by nanosheet‐like g‐C 3 N 4 with extended π‐conjugation. Compared with bulk g‐C 3 N 4 , the nanosheet structure promotes electron delocalization, facilitates interfacial charge transfer, and enhances the generation of reactive oxygen species, thereby accelerating the photodegradation of surface‐bound fouling species. In‐situ electron paramagnetic resonance spectroscopy provides strong evidence for the dynamic formation of delocalized electrons and radical intermediates during regeneration. As a result, the sensor exhibits complete signal recovery within 12 min under sunlight and maintains high detection accuracy over 35 regeneration cycles, with a detection limit of ~ 70 nM. This work provides a mild solution to the design of regenerable sensing platforms.