Designing ultrathin Ag-emb e dde d g-C 3 N 4 nanocomposites for enhanced disinfection performance under visible light

Using ammonium chloride (NH 4 Cl) as a gas template, we conveniently fabricated ultrathin twodimensional layered silver-embedded graphitic carbon nitride nanosheets (AgCNS) by melamine blowing method with triazine groups of pristine graphite carbon nitride. Compared with bulk g-C 3 N 4 (BCN) and g-C 3 N 4 nanosheets (CNS), the antibacterial activity of the optimized AgCNS-5 at a minimum inhibitory concentration (MIC) of 40 ppm against Escherichia coli ( E. coli ) was significantly enhanced. Under visiblelight irradiation, E. coli could be completely killed by 100 mu g center dot mL -1 of AgCNS-5 within 30 min. The mechanism of enhanced antibacterial activity was systematically investigated by ultraviolet-visible diffuse reflectance spectra (UV-vis DRS), photoluminescence spectra (PL), electrochemical impedance spectroscopy (EIS), and photogenerated current densities. Surface plasmonic resonance (SPR) of Ag nanoparticles (NPs) with g-C 3 N 4 was found to lead to an enhancement of visible light absorption and an acceleration of photo-induced electron-hole migration/separation, which is responsible for the enhanced photocatalytic bactericidal performance. Through trapping experiments and electron spin resonance spectroscopy (ESR) techniques, the bactericidal mechanism was revealed that the species of center dot O 2 - and center dot OH play important roles in antibacterial process. Considering the facile preparation and excellent performance, AgCNS-5 may be a promising and competitive visible-light-driven candidate toward sterilizing agent. (c) 2022 Elsevier B.V. All rights reserved.