Breaking the peroxymonosulfate activation barrier: B-induced non-radical for scalable antibiotic mineralization

The inherent kinetic challenges posed by the robust OO and OH bonds in peroxymonosulfate (PMS) significantly hinder contaminant degradation in advanced oxidation processes (AOPs). In this study, we develop a boron‑nitrogen coordinated cobalt single-atom catalyst (SA-Co-BN) through defect-assisted atomic confinement to overcome these limitations. Both experimental and theoretical investigations demonstrate that the low electronegativity of boron induces charge redistribution at the cobalt sites, thereby synergistically enhancing charge transfer dynamics and lowering proton transfer barriers. This facilitates the selective generation of high-valent cobalt-oxo species (Co(IV)O) and singlet oxygen (¹O₂) as predominant non-radical oxidants, effectively circumventing scavenging effects by background anions. The SA-Co-BN + PMS system achieves 91.2% removal of tetracycline (TC) within 30 min (kinetic constant: 0.071 min^-1), representing more than a twofold increase compared to conventional CoN₄ single-atom catalysts (SACs). Furthermore, it maintains over 80% efficiency across a broad pH range (3-11) and in complex matrices, such as wastewater containing 5 mM Cl^-/CO₃^2-. Quantitative structure-activity relationship analyses reveal strong correlations between contaminant degradation kinetics and molecular descriptors, including hydrophilicity, energy gap (ΔE), and electrophilicity index. Importantly, a continuous-flow reactor employing immobilized SA-Co-BN exhibits operational stability for 680 min with 80% contaminant removal, while toxicity assessments confirm a significant reduction in the ecotoxicity of degradation intermediates. This work establishes an atomic-scale design principle for heteroatom-modulated SACs, thereby advancing non-radical oxidation technologies toward practical applications in water purification.