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

Abstract 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.