Dual-functional electrocatalyst of defective cobalt-nitrogen-doped porous carbon for enhanced in-situ hydrogen peroxide generation and electro-Fenton tetracycline degradation

Tetracycline hydrochloride (TC) is one of the organic pollutants that can be consistently monitored in the aquatic environment and pose a great threat to the environment. The development of a bifunctional electro-Fenton (EF) catalyst capable of in situ H2O2 production and decomposition to ·OH to degrade the pollutant is an efficient and green approach to deal with antibiotic pollution. The bifunctional catalysts Co, N double doped defective carbon materials were prepared by pyrolysis ball milling method using zeolite imidazolium ester skeleton structural materials (ZIFs) series materials as precursors, which showed more than 80 % selectivity to H2O2 and could basically remove TC within 120 min in EF system. Carbon defects and graphitic nitrogen can effectively improve the selectivity and yield of H2O2, while graphitization degree improves the charge transfer rate, the doping of Co and pyridinic-N contribute to the decomposition of H2O2 into ·OH. The active species present in the Co1/Zn1-NPC/EF system is ·OH, and factors such as coexisting ions, humic acid and water quality have little effect on the efficiency of the degradation of TC in the Co1/Zn1-NPC/EF system, whereas Co1/Zn1-NPC electrocatalytic catalyst has excellent stability and stable treatment performance for a wide range of pollutants, as well as being an environmentally friendly green catalyst without metal leaching. Furthermore, the possible pathways and the toxicity hazard of TC degradation were proposed. The bifunctional electrocatalyst prepared in this research provides a novel strategy for the green and efficient treatment of pollutants in wastewater.