Oxygen atom transfer pathway contribution to Fenton-like reactions driven entirely by non-radicals on low-nuclearity Co-O/N heterogeneous clusters

Low-nuclearity cobalt-oxygen/nitrogen heterogeneous clusters (Co-O/N HCs) activated H 2 O 2 for non-radical oxidation of organic pollutants via unique oxygen atom transfer (OAT) and singlet oxygen ( 1 O 2 ) pathways. The novel Co-O/N HCs were synthesized using a ligand self-polymerization strategy. When applied to high-salinity wastewater, they efficiently degraded tetracycline via 100 % non-radical pathways over a wide pH range, with degradation rates greater than 0.1758 min −1 and no inhibition by Cl - . The confined cluster size (3–5 Co atomic units) and asymmetric nitrogen distribution modified the cobalt atoms' electronic structure, promoting two H 2 O 2 adsorption modes: bridge-adsorbed *O-O* mediated direct oxidation via OAT, while edge-adsorbed *OOH species selectively generated 1 O 2 . This work elucidates the active sites and mechanisms of H 2 O 2 activation, offering key insights for the design of advanced Fenton-like catalysts.