Sustainable fabrication of silver-titania nanocomposites using goji berry (Lycium barbarum L.) fruit extract and their photocatalytic and antibacterial applications

Abstract

• Green synthesis of metal nanocomposites is sustainable and environmentally friendly. • Silver-titania nanocomposites (Ag-TiO 2 NCs) were synthesized using the aqueous extract of goji berries. • FE-TEM morphology shows the embedment of Ag-NPs throughout the surface of TiO 2 -NPs. • Ag-TiO 2 NC (3:1) exhibited the highest photocatalytic degradation of methylene blue. • NCs exhibited potential antibacterial properties against S. aureus and E. coli bacteria. Silver-titania nanocomposites (Ag-TiO 2 NCs) have unique functional attributes due to their photocatalytic and antibacterial properties. In this study, titania nanoparticles (TiO 2 -NPs) were successfully in-situ decorated with silver nanoparticles (Ag-NPs) using the aqueous extract of goji berries (Lycium barbarum L . ) as a bioreducing and stabilizing agent. Different Ag-TiO 2 NCs were synthesized by treating different concentrations of silver nitrate with a specific concentration of TiO 2 -NPs in the presence of fruit extract. The green-synthesized NCs were characterized using several techniques viz., ultraviolet–visible spectrophotometry, X-ray diffractometry (XRD), scanning electron microscopy, field-emission transmission electron microscopy (FE-TEM), Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. XRD analysis revealed the formation of face-centered cubic (fcc) crystals, and FE-TEM analysis revealed the embedment of Ag-NPs throughout the surface of TiO 2 -NPs. The average size of Ag-NPs on TiO 2 -NPs increased from 11.2 ± 3.05 nm to 16.4 ± 4.5 nm with an increase in the concentration of silver ions, and the morphology of Ag-NPs was predominantly quasi-spherical and hexagonal. These NCs exhibited an excellent photocatalytic degradation of an azo dye, methylene blue (MB). The synthesized Ag-TiO 2 NCs (3:1) showed higher photocatalytic degradation efficiency of ∼ 93.4% for MB in 130 min under visible light irradiation. Ag-TiO 2 NC S also exhibited good antibacterial activities towards Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Therefore, the formation of Ag-NPs on the surface of TiO 2 -NPs to form Ag-TiO 2 NCs exhibits eco-friendly photocatalytic degradation of azo dye contaminants as well as antibacterial activity.