Effective photo-electrochemical production of H2O2 and green Fenton reaction on hierarchical Fe/C/N @ ZIF-8 @ACF for abatement of antibiotics in water

Heterogeneous photo-electro-Fenton (HPEF) reaction is a highly efficient process using H2O2 produced by in-situ two electron oxygen reduction reaction (2e ORR) after aerating for the elimination of refractory organic pollutants. Herein, an effective MOFs derived Fe/C/N @ ZIF-8 @ACF composite electrode for HPEF was prepared by loading Fe/C/N derived from Fe-based metal-organic frameworks (Fe-MOFs) and zeolitic imidazolate framework-8 (ZIF-8) on activated carbon felt (ACF). By supplying air, solar light, and low external electric current (32 mA·cm−2) to the cathode, ZIF-8 could generate H2O2 by 2e- ORR process, and Fe/C/N could react with H2O2 to form strong oxidative radicals (·OH). Photocatalysis accelerates the Fenton reaction greatly with the abundant photo-generated electrons. The HPEF activity of different systems for the degradation of antibiotics was compared. The results showed that the degradation rate of antibiotics can be greatly increased with the best of ∼100% within 100 min. Moreover, the electrode could still maintain a high activity after reuse for 4 times, which proved to be highly active, stable, and well recyclable for a rapid HPEF oxidation for abatement of antibiotic pollutants in water.