Heterogeneous photo-electro-Fenton degradation of tetracycline through nitrogen/oxygen self-doped porous biochar supported CuFeO2 multifunctional cathode catalyst under visible light

The nitrogen/oxygen self-doped porous biochar (NO/PBC) and NO/PBC supported CuFeO 2 (CuFeO 2 -NO/PBC) were prepared and mixed as cathode catalysts for gas diffusion electrode (GDE) fabrication. The fabricated GDE could realize H 2 O 2 electrogeneration and activate H 2 O 2 to produce active radicals through NO/PBC and CuFeO 2 , respectively. The GDE with the NO/PBC to CuFeO 2 -NO/PBC ratio of 1:1 (CuFeO 2 -NO/PBC-GDE-1.0) possessed more superior catalytic performance for tetracycline degradation in heterogeneous photo-electro-Fenton (hetero-PEF) system under visible light than other as-fabricated GDEs. The • OH was primary species, and • O 2 - was auxiliary species for hetero-PEF degradation of tetracycline through CuFeO 2 -NO/PBC-GDE-1.0. The electron on the cathode surface and photoinduced electron could accelerate Fe 3+ / Fe 2+ and Cu 2+ / Cu + redox cycle, promoting • OH/ • O 2 - production and tetracycline degradation. The toxicity estimation of tetracycline and intermediates, TOC removal and Escherichia coli growth inhibition confirmed that the remission of overall toxicity, the inhibition of antibacterial property and the mineralization of tetracycline were achieved in hetero-PEF system. • CuFeO 2 -NO/PBC was prepared by hydrothermal method using NO/PBC as a support. • CuFeO 2 -NO/PBC-GDE-1.0 was fabricated for the hetero-PEF degradation of tetracycline. • CuFeO 2 -NO/PBC-GDE-1.0 could generate and activate H 2 O 2 to produce active radicals • Cathode electron and photoinduced electron promoted regeneration of Fe 2+ and Cu + . • Hetero-PEF system relieved the toxicity and antibacterial property of tetracycline.