Visible-light-driven antibacterial photocatalyst based on Ag nanoparticle-decorated N-vacancy g-C ₃ N ₄ nanosheets

The rapid rise of antibiotic resistance threatens global health, highlighting the need for new antimicrobial strategies. Here, we investigated nitrogen vacancies and Ag nanoparticles decoration in carbon nitride (Ag-g-C 3 N 4 -V). Nitrogen vacancies optimized the electronic structure, boosting light absorption and charge separation. Ag nanoparticles induced a synergistic effect via localized surface plasmon resonance and the conjugated C 3 N 4 network, enhancing visible-light photocatalysis. The composite promoted hydrogen peroxide (H 2 O 2 ) generation, a reactive oxygen species with antibacterial activity. The incorporation of Ag synergistically coupled H 2 O 2 generation with Ag + release, leading to enhanced bactericidal performance. Treatment with Ag-g-C 3 N 4 -V reduces the survival rates of E. coli and S. aureus by approximately 39% and 58% respectively compared to the control group; under light conditions, Ag-g-C 3 N 4 -V lowers the survival rates of E. coli and S. aureus to only 16% and 6%, showing a more remarkable bactericidal effect. This work offers a strategy for designing multifunctional photocatalysts against bacterial infections with potential biomedical applications.