Effective catalysis and antibacterial activity of silver and gold nanoparticles biosynthesized by Phlogacanthus turgidus

In this work, an environmentally friendly and cost-effective synthetic method of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) was successfully performed using aqueous extract of Phlogacanthus turgidus (PT) leaves. The biosynthesis of nanoparticles was optimized for reaction conditions including concentration of metallic ions, temperature, and time using the measurement of UV–Vis spectroscopy. The nanoparticles were well characterized by analytic techniques such as Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), high-resolution transmission electron microscope (HR-TEM), and selected area electron diffraction (SAED). The morphological data showed that PT-AgNPs possessed the spherical shape with the size distribution ranging from 5 to 15 nm with a mean size of 10 nm while PT-AuNPs existed in the multiple shape with the size distribution ranging from 5 to 20 nm with a mean size of 12 nm. The antibacterial behavior showed that PT-AgNPs possessed high bioactivity against four bacterial strains including Bacillus subtilis , Staphylococcus aureus, Salmonella typhi , and Escherichia coli. Moreover, the catalytic activity of the biogenic nanoparticles was investigated for catalytic reduction of 2-nitrophenol, 3-nitrophenol, and rhodamine B. The kinetic data showed that the nanoparticles were excellent catalysts with potential applications for environmental treatment. Graphical abstract