Delocalized electron-enhanced photo-regeneration based on nanosheet g-C3N4 enables reusable electrochemical antibiotic sensing

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. Graphical abstract