Synergistic Catalytic Ozonation Mediated by Dual Active Sites of Oxygen Vacancies and Defects in Biomass-Derived Composites for Long-Lasting Water Decontamination

Environmental decontamination relies on low-cost, sustainable materials to drive diverse catalytic redox reactions. In this work, we used low-cost biomass to develop nanocomposites of N-doped carbon-supported zinc oxide (ZNC400) at a low temperature (400 °C), which exhibited ultrahigh activity in heterogeneous catalytic ozonation (HCO) for organic water decontamination. Our experimental and computational studies revealed the collaborative functions of dual active centers of defective carbons and oxygen vacancies (OVs)-containing zinc oxide (ZnO) at the composite interface for successive ozone (O3) adsorption and catalytic decomposition, respectively. Inspiringly, OVs on ZnO will spontaneously dissociate water molecules (H2O) to form surface hydroxyl groups (–OH) as key intermediates to accelerate O3 decomposition. This synergistic interplay results in the continuous generation of hydroxyl radicals (•OH) and maintains over 90.2% atrazine (ATZ) removal over five successive cycles, endowing ZNC400 with substantial reusability. Furthermore, four ATZ degradation pathways were proposed, and the corresponding toxicity was evaluated by the embryonic development of zebrafish in the treated water. Overall, the engineered dual-function catalyst effectively addresses the long-standing issue of poor stability of carbon materials in HCO and offers high-performance, cheap, and green catalysts for advanced water purification.