Selective H2O2 production on N-doped porous carbon from direct carbonization of metal organic frameworks for electro-Fenton mineralization of antibiotics

Abstract Cathode materials with high activity, selectivity and stability are essential to efficient electrochemical H2O2 generation. Herein, nitrogen-doped porous carbon (NPC) is synthesized via direct calcination of nitrogen-containing metal organic framework. The N doping into porous carbon boosts H2O2 generation, thus enhancing electro-Fenton activity. The NPC cathode exhibits a highly selective reduction of O2 to H2O2 (96.4% at pH 1 and −0.1 V vs SCE) and H2O2 production rate reaches 52.3 mmol·L−1 h−1 (pH 1, −0.6 V vs SCE). Moreover, NPC achieves a high current efficiency of 87.7% for H2O2 production (pH 1, −0.5 V vs SCE). The removal efficiency of oxcarbazepine antibiotics achieves 100% in 10 min ([Fe2+] = 1.0 mmol L−1, C0 = 12.61 mg L−1 (50 μmol L−1), pH 1–5, −0.5 V vs SCE), and total organic carbon (TOC) removal efficiency reaches 90.7% in 60 min. Additionally, the removal efficiency of other antibiotics of prednisolone, chloramphenicol and thiamphenicol reaches 97.0–98.8% in 10 min and the TOC removal efficiency achieves 70.8–92.0% in 60 min. Moreover, NPC shows an excellent electrochemical stability. This work is valuable for designing electro-Fenton catalysts with high activity, selectivity and stability.