Green synthesis of Ag-ZnO nanocomposites using Fraxinus floribunda bark extract and their photocatalytic and antioxidant properties

In this work, a green synthesis route of Ag-ZnO (Silver-zinc oxide) nanocomposites was investigated employing aqueous extract of Fraxinus floribunda bark. The synthesized Silver-zinc oxide nanocomposites were studied using techniques such as ATR FTIR, UV- Vis, SEM-EDX, and XRD. Based on the results, the optimal conditions for the synthesis of silver-zinc oxide nanocomposites were an Ag concentration of 8%, 80°C, and a pH of 7-8. The ATR-FTIR tests confirmed the existence of flavonoid, phenols and characteristic bands of Silver and Zinc oxide bands, which work as stabilizing and reducing agents. When Silver-zinc oxide nanocomposites were evaluated for their photocatalytic potential under visible light irradiation using the Methylene Blue (MB) dye, 98 percent photodegradation was observed within 30 minutes for 8% Silver-zinc oxide nanocomposites. The significant photocatalyst for the maximum degradation of MB was shown by 8% Silver-zinc oxide nanocomposites as it showed the higher reaction rate constant compared to other nanocomposites. The antioxidant activity of the nanoparticles was studied against radicals of DPPH (2,2-diphenyl-1-picrylhydrazyl) to assess their ability to capture radical species. The highest percentage scavenging activity of 78% was shown by 8% Ag-ZnO nanocomposite. Ag nanoparticles found on the zinc oxide surface enhances photocatalytic degradation by minimizing the photo-induced recombination charge carriers within the nanocomposites.