Effective low-powered photocatalytic disinfection via synchronous introduction of oxygen dopants and carbon defects in carbon nitride

Establishing an effective metal-free photocatalyst for sustainable applications remains a huge challenge. Herein, we developed ultrathin oxygen-doped g-C₃N₄ nanosheets with carbon defects (OCvN) photocatalyst via a facile gas bubble template-assisted thermal copolymerization method. A series of OCvN with different dopant amounts ranging from 0 to 10% were synthesized and used as photocatalysts under illumination of low-power (2 × 18 W, 0.18 mW/cm²) and commercially available energy-saving light bulbs. Upon testing for photocatalytic Escherichia coli inactivation, the best-performing sample, OCvN-3, demonstrated an astonishing disinfection activity of over 7-log reduction after 3 h of illumination, boasting an 18-fold improvement in its antibacterial activity compared to that of pristine g-C₃N₄. The enhanced performance was attributed to the synergistic effects of increased surface area, extended visible light harvesting, improved electronic conductivity, and ultralow resistance to charge transfer. This study successfully introduced a green photocatalyst that demonstrates the most effective disinfection performance ever recorded among metal-free g-C₃N₄ materials. Its disinfection capabilities are comparable to those of metal-based photocatalysts when they are exposed to low-power light.