Efficient one-pot biosynthesis of silver nanoparticles using Entada spiralis stem powder extraction

Abstract

Biosynthesis of noble metal nanoparticles is a vast developing area of research. In the present study, silver nanoparticles (Ag-NPs) are synthesized from aqueous silver nitrate through a simple and biosynthetic route using aqueous extract of Entada spiralis stem powder, which acted simultaneously as a reductant and stabilizer. The prepared samples are characterized using UV–visible, XRD, TEM, SEM, EDX, zeta potential and FTIR techniques. The formation of Ag-NPs is evidenced by the appearance of the signature brown color of the solution and UV–Vis spectra. Formation of E. spiralis/Ag-NPs is determined by UV–Vis spectroscopy, where surface plasmon resonance (SPR) absorption maxima can be observed at 400–450 nm from the UV–Vis spectrum at moderate temperature (~ 52 °C). The XRD analysis shows that the Ag-NPs at moderate temperature have a face-centered cubic structure (FCC). Well-dispersed Ag-NPs with anisotropic and isotropic morphology for E. spiralis/Ag-NPs at room and moderate temperature, with sizes of around 39.82 and 17.56 nm, are observed in TEM images. The SAED pattern exhibits the cubic lattice structure for Ag-NPs, and the d-spacing value of the crystalline structure of Ag-NPs measures around ~ 0.14 nm, which is attributed to the Ag-NPs of the (220) cubic plain at an angle of 64.78°. The spherical shapes of Ag-NPs with proper distribution for both reaction temperatures are observed in SEM images. The FTIR analysis reveals the main functional groups in the E. spiralis stem powder extract involved in the binding of Ag-NPs. The overall performance of the biosynthesis of Ag-NPs indicates that the formation of Ag-NPs using E. spiralis stem powder extract is temperature-dependent.