Li, Y.Yan, M.Lin, H.Wang, S.Duan, X.Wu, X.L.2025-05-132025-05-132025Applied Catalysis B: Environmental, 2025; 361:124663-1-124663-100926-33731873-3883https://hdl.handle.net/2440/144514This study developed an innovative reduction-oxidation coupling process for treatment of refractory organic wastewater. We constructed a series of N5-coordinated transition metals (TMs) (TMs = Mn, Fe, Co, Ni, Cu) singleatom sites supported on nitrogen-rich carbon nitride (SA-TM-C3N5) for electrochemical generation of the surfaceadsorbed hydrogen atom (H*) and hydroxyl radical (•OH). The SA-Co-C3N5 exhibited the highest activity for production of the H*-•OH redox pair, which effectively degraded refractory nitro-organic micropollutants via the parallel reduction-oxidation pathways. The SA-Co-C3N5-mediated electro-Fenton-like system showed high removal efficiency (99 %) and mineralization capacity (78 %) toward metronidazole (MNZ) with low energy consumption (0.019 kWh (g TOC)–1 ). The trifunctional properties of the H* have contributed to the reduction of nitro compounds, the 2e– ORR for H2O2 production and the Fenton-like catalysis for •OH generation. This work sheds lights on the development of advanced reduction-oxidation coupling process for green and sustainable water purification.en© 2024 Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.Single-atom catalysts; Coordination regulation; Electro-Fenton; Oxidation-reduction processes; Adsorbed hydrogenJournal article10.1016/j.apcatb.2024.124663712649Wang, S. [0000-0002-1751-9162]Duan, X. [0000-0001-9635-5807]