Enhanced antibacterial and visible light driven photocatalytic activity of graphene oxide mediated Ag₂O nanocomposites

Hazardous microorganisms and poisonous pigments found in industrial effluent can have detrimental effects on the environment and human health. This study investigates the synthesis and characterization of graphene oxide (GO), silver oxide (Ag₂O) nanoparticles (NPs), and graphene oxide-based silver oxide (GO/Ag₂O) nanocomposite, highlighting their enhanced antibacterial and visible light-driven photocatalytic activities. Modified Hummers’ method, sol-gel auto-combustion method, and low-cost sonication method were used to prepare GO, Ag₂O NPs, and GO/Ag₂O nanocomposite with different wt% (1, 5, 10, and 15) of GO, respectively. These synthesized materials were characterized using various characterization techniques such as, UV-vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), and Transmission electron microscope (TEM). Particle size was calculated using Gaussian fitting of XRD, which was found to increase from 20 to 25 nanometres (nm). The optical energy band gap was calculated using a Tauc plot, which decreased from 1.77 to 1.14 electron Volts (eV), respectively. The valence state of Ag (Ag⁺) for Ag₂O, GO-1/Ag₂O, and GO-15/Ag₂O are confirmed by X-ray photoelectron spectroscopy (XPS). The degradation of methylene blue (MB) dye was done in exposure to sunlight at various time periods using these synthesized materials as photocatalysts to evaluate their photocatalytic activity. GO (15 wt%)/Ag₂O nanocomposite showed the best photocatalytic activity among all synthesized materials by the degradation of MB dye to 90% in 120 min under the sun. In addition to excellent photocatalytic activity, GO (15 wt%)/Ag₂O nanoparticles exhibited excellent antimicrobial activity. It showed the highest inhibitory range and lowest inhibitory concentration against Staphylococcus aureus and Escherichia coli among all synthetic materials. This demonstrates its potential as a versatile material with excellent photocatalytic and antimicrobial properties, making it promising for many applications in environmental and medical care.