One-pot green synthesis of Au-Ag bimetallic nanoparticles from Lawsonia inermis seed extract and its catalytic reduction of environmental polluted methyl orange and 4-nitrophenol

Background: Bimetallic nanoparticles (BNPs) are used in attractive applications in the medicinal, green catalyst, optics, electrochemical and so on. Apart from the catalytic activity, the chemical synthesized BNPs is less energy and environmentally highly toxic. Hence, Au-Ag BNPs prepared by the green synthesis method is suggested to be eco-friendly and have a potential catalytic reduction/degradation activity against environmentally polluted organic dyes. Materials and method: In this present work, Ultrasound-Assisted green synthesis of Gold-Silver Bimetallic Nanoparticles (Au-Ag BNPs) was synthesized from Lawsonia inermis seed extract aqueous fraction. The effects of the extract volume, metal ions concentration, pH, and temperature were investigated to determine the optimum conditions of the synthesis of Au-Ag BNPs. Results and discussion: UV-vis absorbance of the surface Plasmon resonance centre at 537 nm was confirmed the product of Au-Ag BNPs. FT-IR spectroscopy to determine the phytochemicals groups of the plant extract and Au-Ag BNPs. High-resolution transmission electron microscopy image of Au-Ag BNPs shows polygonal, spherical and irregular shaped with particle sizes 15-35 nm. Under UV-vis the light source, the obtained BNPs had a strong photocatalytic reduction/degradation activity against 4-nitrophenol and methyl orange dye in the presence of NaBH4. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.