Low-Temperature Thermocatalytic Disinfection of <i>Escherichia coli</i> Using Co-Doped MnO_<i>x</i> Bimetallic Oxide Catalysts

Pathogenic <i>Escherichia coli</i> in wastewater necessitates energy-efficient disinfection methods. This study developed cobalt-doped manganese oxide (CoMnO _<i>x</i> ) catalysts via redox-hydrothermal synthesis for low-temperature thermocatalytic disinfection. Systematic characterization (XRD, SEM, and XPS) revealed that Co doping induced a phase transition from α-MnO₂ to δ-MnO₂, forming nanoflower-like structures with enhanced oxygen vacancies and optimized Mn⁴ ⁺/Mn³ ⁺ ratios. The optimized Co₁Mn₁O _<i>x</i> catalyst achieved complete inactivation of <i>E. coli</i> K-12 (5.3 lg CFU mL^-1) within 1 h at 50 °C, significantly outperforming pure MnO₂ and Co₃O₄. Mechanistic studies identified superoxide radicals (·O₂ ^-) and singlet oxygen (¹O₂) as the dominant reactive oxygen species (ROS), generated through lattice oxygen release and oxygen vacancy regeneration via the Mars-van Krevelen mechanism. ROS-induced membrane damage led to intracellular leakage and enzyme inactivation. The catalyst demonstrated good stability (>99.5% efficiency after four cycles) and efficacy across a relevant pH range (5.5-7.5). This work presents a sustainable strategy for efficient low-temperature water disinfection using transition metal oxide catalysts.