Coordination engineering enables highly selective generation of carbonate radical for enhanced Fenton-like reactions

Overturning the conventional wisdom, recent studies demonstrated that bicarbonate ions (HCO) serve as promoters instead of inhibitors in heterogeneous Fenton-like processes. Nevertheless, the interfacial activation mechanisms of HCO and HO remain insufficiently understood, hindering the rational development of efficient catalytic processes. Herein, we report a coordination-regulated Co single-atom catalyst (SAC) that enables a highly selective pathway for carbonate radical (CO) generation. By constructing a six-coordinated CoN configuration (Co-N/C-T), the system achieved rapid and efficient degradation of sulfamethoxazole (SMX, 96.9%) within 60 min, with CO accounting for 98.9% of the total reactivity. Mechanistic insights from Fourier-transform infrared (FTIR) and density functional theory (DFT) calculations revealed the preferential adsorption and dissociation of peroxymonocarbonate (HCO) intermediate at CoN sites, facilitating selective generation of CO as the dominant reactive oxygen species (ROS). The Co-N/C-T Fenton-like system also exhibited robust performance and excellent recyclability at environmentally relevant concentrations across various realistic water matrices. Furthermore, a structure-reactivity correlation grounded in electronic descriptors revealed the system’s high selectivity toward electron-rich amine-containing antibiotics and their analogues, offering a targeted strategy for contaminant removal under complex water matrices. These findings provide mechanistic insights for advancing next-generation Fenton-like systems across diverse water treatment scenarios.