Coordination Reconstruction Enhanced Synergistic Nonradical Oxidation Pathways in Cobalt Single-Atom Catalysts for...

Limited synthetic efficiency and high costs constrain industrial production of single-atom catalysts (SACs) despite their superior catalytic performance. We report a scalable and economical solid-state pyrolysis strategy for cobalt single-atom catalysts (Co-SACs) costing ∼$35 kg^-1. Hydrothermal O-substitution precisely engineers the coordination environment from Co-N3O1 to Co-N2O2. The upshifted d-band center and enhanced electron delocalization of Co-N2O2 decrease electron density at the Co site, strengthening peroxymonosulfate (PMS) adsorption. Electron paramagnetic resonance, probe experiments, and electrochemical tests synergistic confirmed that Co-N2O2 significantly promotes nonradical processes, including the generation of singlet oxygen, high-valent metal oxo species, and electron transfer processes. The resultant Co-N2O2 catalyst achieved over 98% degradation of high-concentration sulfamethoxazole (100 mg L^-1) within 10 min. The kilogram-scale Co-N2O2 (kg-Co-N2O2) demonstrated outstanding efficiency in treating landfill leachate (2548 mg L^-1 TOC removal) and preeminent stability in 14 cycles and 10 h membrane dynamic experiments. This work provides both fundamental elucidation into coordination engineering and a practical solution for large-scale production of SACs in environmental remediation.