Green Synthesis of Pseudo-Cubic Ag/Ni Bimetallic Nanoparticles using Senna occidentalis Leaf Extract

Abstract

This study reports plant-mediated co-reduction approach for the synthesis of Ag/Ni bimetallic nanoparticles (Ag/Ni BNPs). In view of sustainability development, aqueous leaf extract of an indigenous Senna occidentalis (coffee senna) acted as a reducing agent. Cold extraction was carried out on the biodiversity plant using water and methanol as solvent media by way of “green” synthesis. Qualitative analysis was done to identify possible secondary metabolites present in the extract. Synthesis of the nanohybrid was achieved using two different precursor concentrations at 70°C. Techniques including Uv-visible spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy were engaged for optical, morphological and compositional characterisation of the Ag/Ni BNPs, respectively. The reaction colour changed from green to dark brown due to the excitation of electron and change in the electronic energy levels of metal nanoparticles. Presence of nickel in the nanohybrid resulted in blue shift in the absorbance wavelengths when compared with the corresponding monometallic Ag NPs (341 to 327 nm). The optical property displayed by Ag/Ni BNPs is a pointer for potential application as optical material.