Effect of single and combined (core/shell) biosynthesis of nanoparticles (Ag and ZnO) on their photocatalytic and antimicrobial activities

Synthetic silver (Ag) and zinc oxide (ZnO) nanoparticles, singly or in core/shell form, have received significant attention for their numerous biomedical and health applications. This is due to their biocompatible, non-toxic, and catalytic nature. This work describes a novel approach to biosynthesizing Ag, ZnO, Ag/ZnO, and ZnO/Ag NPs from the leaf extract of Acalypha fruticose (AF). The study verified the formation of the nanoparticles through Fourier transform infrared (FTIR) and ultraviolet-visible (UV-Vis) spectra examination. The role of AF extract, as a reducing and capping agent, was revealed via phytochemical and FTIR studies. The nanoparticles were stable and crystallized, with crystal sizes ranging from 14 nm to 77 nm, according to X-ray diffractometer (XRD) examination. The crystallinity of Ag NPs increased significantly in the core/shell structure compared to single nanoparticles, especially in the shell position. The nanoparticles' crystal structure features were strongly associated with their shapes and sizes. The transmission electron microscopy (TEM) examination indicated that the nanoparticles' size ranged from 16 to 90 nm. The antimicrobial activity of the Ag NPs exhibited the highest inhibition efficiency, while the other nanoparticles also demonstrated promising results compared to previous studies. Additionally, the ZnO NPs were highly effective in degrading organic pollutants (dyes), achieving a remarkable degradation rate of 99.48% for methylene blue (MB) within 210 min.