Engineering Atomic Ag₁–N₆ Sites with Enhanced Performance of Eradication Drug-Resistant Bacteria over Visible-Light-Driven Antibacterial Membrane

Abstract

Utilizing visible light for water disinfection is a more convenient, safe, and practical alternative to ultraviolet-light sterilization. Herein, we developed silver (Ag) single-atom anchored g-C₃N₄ (P-CN) nanosheets (Ag₁/CN) and then utilized a spin-coating method to fabricate the Ag₁/CN-based-membrane for effective antibacterial performance in natural water and domestic wastewater. The incorporated Ag single atom formed a Ag₁-N₆ motif, which increased the charge density around the N atoms, resulting in a built-in electric field ∼17.2 times stronger than that of pure P-CN and optimizing the dynamics of reactive oxygen species (ROS) production. Additionally, the Ag₁-N₆ motif inhibited the release of Ag ions, ensuring good biocompatibility. Based on the first-principles calculation, the adsorption energy of O₂ on the Ag₁/CN (-0.32 eV) was lower than that of P-CN (-0.07 eV), indicating that loaded Ag single atom can lower the energy barrier for O₂ activation, generating extra *OH radicals that cooperated with *O₂^- to effectively neutralize bacteria. As a result, the Ag₁/CN powder-catalyst with the concentration of 30 ppm demonstrated a 99.9% antibacterial efficiency against drug-resistant bacteria (<i>Escherichia coli</i>, <i>Staphylococcus aureus</i>, kanamycin-resistant <i>Escherichia coli</i>, and methicillin-resistant <i>Staphylococcus aureus</i>) under visible-light irradiation for 4 h. This efficacy was 24.8 times higher than that of the P-CN powder catalyst. Moreover, the Ag₁/CN-based-membrane can maintain a 99.9% bactericidal efficiency for natural water and domestic wastewater treatment using a homemade flow device, demonstrating its potential for water disinfection. Notably, the visible-light-driven antibacterial efficiency of the Ag₁/CN catalyst outperformed the majority of the reported g-C₃N₄-based catalysts/membranes.