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In this study, we adeptly synthesized a composite material comprising graphene and transition metal iron, which was then immobilized onto the nickel foam (NF) substrate to expedite electron transfer and catalyze the generation of hydroxyl radicals (·OH), thereby effectively degrading the target pollutants. In this process, dissolved oxygen molecules were converted into H 2 O 2 through a two-electron pathway, and the main reaction species (·OH) was responsible for further activation at the cathode. Furthermore, the formation of Fe-C bonds in rGO/Fe 2% -NF cathode not only promoted direct electron transfer but also improved the structural and performance stability of the cathode. [Display omitted] • By adjusting the ratio of graphene and Fe, an electro-Fenton cathode with Fe-C bond was developed. • Dissolved oxygen molecules were converted into H 2 O 2 through a two-electron pathway. • The Fe-C bonds enhances the electron transport efficiency and stability of the electrode. • The toxicity calculation of intermediate products showed a significant downward trend. The pervasive presence of aromatic organic pollutants, encompassing antibiotics and chemical raw materials, poses a significant and pressing threat to human health and safety. While the conventional electro-Fenton approach effectively addresses the challenges of superior efficacy, reduced energy consumption, and easy regulation through H 2 O 2 supplementation, it remained confronted with challenges, including the formation of iron sludge and suboptimal electron utilization efficiency in H 2 O 2 generation. Here, we adeptly synthesized a composite material comprising graphene and transition metal iron, which was then immobilized onto the nickel foam substrate to expedite electron transfer and catalyze the generation of hydroxyl radicals (·OH), thereby effectively degrading the target pollutants. The rGO/Fe 2% -NF cathode system showed excellent removal effects on sulfadiazine, 2,2′,4,4′-tetrehydroxybenzophenone, and rhodamine B (100% within 120 min). In this process, dissolved oxygen molecules were converted into H 2 O 2 through a two-electron pathway, and the main reaction species (·OH) was responsible for further activation. Furthermore, the formation of Fe-C bonds in rGO/Fe 2% -NF cathode not only promotes direct electron transfer but also improves the structural and performance stability of the cathode. Notably, the toxicity assessment of intermediates displayed a marked decline, signifying the potential of the rGO/Fe 2% -NF cathode system to ameliorate the imminent risks posed by micropollutants. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel flow-anode, CeO x /CB, was introduced in electro-oxidation. • Ce(IV)/Ce(III) redox cycle accelerated the electron transfer directionally. • The loading of CeO x actuated efficient •OH generation. • Acetaminophen degradation rate was 2.3–2.9 times higher than the control. • CeO x /CB achieved high current efficiency and low energy consumption. Electrochemically active materials can effectively alleviate mass transfer restriction by adding them as flow-anodes into the electrochemical reactor. However, conventional flow-anode materials display a low •OH yield. Here, a novel flow-anode, CeO x /carbon black (CB), demonstrates superior electrocatalytic degradation efficiency of organic pollutants. The acetaminophen degradation kinetic constant of CeO x /CB was calculated to be 2.3–2.9 times higher than that of CB. CeO x /CB achieved a higher current efficiency of 66.4 % and relatively lower energy consumption of 157.8 kWh/kg COD compared with other GAC or γ-Al 2 O 3 -based flow-anodes. The mechanistic analyses demonstrated that rapid electron transfer, strong water adsorption, and low reaction energy barrier of CeO x /CB actuated efficient •OH generation. Moreover, Ce(IV)/Ce(III) redox cycle crucially acted as an "electron porter" to accelerate the electron transfer from adsorbed H 2 O molecules to CB substrate directionally in the electro-oxidation process. This work provides a feasible manner for the development of flow-anodes utilizing the advantage of the Ce(IV)/Ce(III) redox cycle. [ABSTRACT FROM AUTHOR]