Green synthesis of nano-Ag2O using Moringa oleifera leaves for efficient photocatalytic and antimicrobial applications

Abstract

In this research, silver oxide nanoparticles (Ag₂O NPs) were synthesized through a green synthesis method utilizing the leaf extract of Moringa oleifera, and their antimicrobial activity against Gram-positive and Gram-negative bacteria was evaluated. Furthermore, the effectiveness of the green-synthesized Ag₂O NPs as photocatalysts was investigated by degrading Congo red dye and ciprofloxacin antibiotics. Various sophisticated tools, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and energy-dispersive X-ray spectroscopy (EDX), were implemented to analyze the synthesized product. From the XRD data, the crystallite size was computed by deploying several model equations; the crystallite size was 2–126 nm. An FTIR spectrophotometer confirmed the activating group of the Ag₂O NPs, and the thermogravimetric analyzer revealed nearly 9% weight loss in two stages. SEM analysis revealed that the Ag₂O NPs are spherical and rod-shaped. The dye degradation percentage was assessed utilizing a UV-vis Spectrophotometer depending on different parameters, and 84% (Congo red dye) and 46% (ciprofloxacin) were found to be the highest degradation percentages at 120 min for 0.1 g of Ag₂O catalyst. The Ag₂O NPs synthesized through a green approach exhibited noteworthy antimicrobial activity against both Gram-positive (Staphylococcus aureus and Bacillus megaterium) and Gram-negative (Escherichia coli and Salmonella typhi) bacteria. The diameter of the zone of inhibition was larger in the case of E. coli (14 mm) than S. aureus (13 mm), B. megaterium (12 mm), and S. typhi (12 mm).