The Synthesis And Antibacterial Properties Of ZnO/Ag/rGO Composites

The development of highly effective and durable antimicrobial materials is an effective way to solve the current bacterial contamination.In this paper,zinc oxide?ZnO?and silver nanoparticles?AgNPs?were loaded on reduced graphene oxide?rGO?sheets by a simple chemical method to obtain ZnO/Ag/rGO composite antibacterial materials.Under visible light,efficient and durable antibacterial property was achieved with the visible light photocatalytic activity of ZnO and surface plasmon resonance?SPR?effect and excellent antibacterial performance of AgNPs.The main research contents are as follows:1.ZnO/Ag/rGO composites were successfully prepared by in situ reduction at room temperature with NaBH₄ as reducing agent.The morphology analysis showed that the spherical nano-silver particles and lamella-like ZnO particles with a diameter of about 50 nm were loaded on the rGO sheet.Due to the visible light catalytic activity of ZnO,the charge transfer mechanism of Ag and the excellent antibacterial ability of AgNPs,a synergistic sterilization of reactive oxygen radical?ROS?and Ag⁺was achieved to kill bacteria.Highly effective antibacterial with low Ag content was achieved under visible light.The minimum inhibitory concentration?MIC?against E.coli and S.aureus was 80 ppm and 60 ppm,respectively.The composites showed good stability.2.ZnO/Ag/rGO composites were prepared by ethanol solvothermal method using environmentally friendly reagent ethanol as reducing agent and solvent.The diameter of the Ag particles in the composites were about 200 nm.Micron-sized hexagonal particles and spherical particles smaller than 10 nm supported on the rGO sheet were ZnO.Due to the large size,the photocatalytic ability of ZnO was weakened,resulting in a slight decline in the antibacterial properties of the composite.The MIC against E.coli and S.aureus was 100 ppm and 80 ppm,respectively.The stability of composite antibacterial materials was also relatively reduced due to the influence of particle size.Only 20%of Ag remains in the composites when dispersed in water for 15 days.3.ZnO/Ag/rGO composites were prepared by ethylene glycol solvothermal method with ethylene glycol as solvent and reducing agent.The ZnO particles with a diameter of about 20-50 nm and the Ag particles with an average diameter of less than100 nm were uniformly decorated on the rGO sheet.The reduction of particle size significantly improved the antimicrobial activity and stability of the composites.The MIC against E.coli and S.aureus was 80 ppm and 40 ppm,respectively.When the composite material was dispersed in water for 15 days,80%of Ag remained in the composite material,achieving efficient and long-lasting sterilization.