Single-Atom Copper@Carbon Nanospheres for Catalytic Ozonation: Parallel Dual Surface Oxidation Pathways for Broad-Spectrum Water Pollutant Removal.

Heterogeneous catalytic ozonation (HCO) is a promising strategy for removing organic pollutants from wastewater, but its practical deployment is limited by the scavenging effects of coexisting constituents (e.g., inorganic anions and humic acids) on hydroxyl radicals (•OH). Herein, we developed atomically dispersed single-atom copper@carbon nanospheres (Cu-NC-3), which effectively decompose ozone (O3) to generate surface atomic oxygen (*O), as confirmed by the in situ Raman experiments and theoretical calculations. The *O species rapidly degrade 60% of oxalic acid (OA) within 1 min, while protonation of *O produces surface-confined hydroxyl radicals (•OHad) that achieve 94.7% removal of benzoic acid (BA) and other aromatic compounds. Compared to ozonation alone, the O3/Cu-NC-3 system enhances OA and BA removal by 34.5- and 1.5-fold, respectively. Atomic-level Cu dispersion induces carbon defects that enrich surface O3, and Cu-N4 coordination sites promote its conversion to *O and •OHad. This dual-oxidation mechanism effectively ensures and enables broad-spectrum pollutant removal and exceptional catalytic stability under long-term operation. Therefore, the O3/Cu-NC-3 system offers a robust and efficient approach for treating real wastewater containing diverse interfering species.