Interfacial engineering of Mg₃O(CO₃)₂-bound cobalt nanosheets via one-pot synthesis for PMS-driven water decontamination

Abstract Antibiotic contamination threatens global water security and health. Peroxymonosulfate (PMS) activation provides an environmentally sustainable approach for water remediation, but conventional cobalt-based catalysts face low atomic utilization and metal leaching issues. Herein, we developed a novel a CoMg/HMTA composite through a one-step hydrothermal method using hexamethylenetetramine (HMTA) and magnesium salts enable the dispersion of cobalt nanosheets on Mg3O(CO3)2 substrates. The alkaline carrier Mg3O(CO3)2 not only stabilizes Co sites but also minimizes Co leaching (0.18 mg/L). The optimized system achieved 99.6% metronidazole (MNZ) degradation in 30 min and maintained >99% efficiency over six cycles, demonstrating superior catalytic performance. This strategy was generalized to Cu and Ni systems, confirming the universal stabilizing role of Mg-based carriers. Mechanistic studies using EPR spectroscopy and quenching tests revealed a multi-level degradation mechanism involving radicals (SO4•-, O2•−) and non-radicals (1O2), showing robust performance in various water matrices. This work provides a scalable platform for designing stable persulfate activators against emerging contaminants.