Design of green sustainable protocol for preparation of gold nanoparticle An effective catalyst for organic synthesis

Abstract

Looking at the recent advancements and the requirements of heterogeneous catalysts with industrial importance, this study represent the detailed report on gold nanoparticle GNPs as an efficient, green and sustainable catalyst. In this study, GNPs have been successfully fabricated by the bio reduction route using soil extract Aspergillus trinidadensis VM ST01 OL587588 fungi as a reducing and capping agent without any solvent interference. The GNPs were grown and stabilized by a two-step one-pot method, without any influence of chemical reactants. Three different methodologies, i.e. whole cell biomass, cell free extract and lyophilized biomass, have been established for the synthesis of GNPs. Based on the obtained results, synthesis of GNPs by lyophilized biomass is most suitable process. Characteristics of all the prepared GNPs were investigated using various microscopic and spectroscopic techniques. GNPs were roughly spherical in shape. Water dispersion study of GNPs has shown a stable dispersion in a broad range of 2 12 pH. The stirring and precursor salt concentration has influenced the kinetics involved in the fabrication process. Stoichiometric data has shown 3.5 × 1020 gold atoms per gram of biomass with diameters of around 35 nm, as determined with High-Resolution Transmission Electron Microscopy HR- TEM. Zeta potential and Powder X-Ray Diffraction P-XRD studies have elucidated the crystalline nature of GNPs. Presence of participating functional groups were examined with Fourier Transform Infra-Red Spectroscopy FT-IR. Synthesized GNPs were analyzed for surface morphology by Scanning Electron Microscope SEM. The thermal stability of the lyophilized GNPs sample and capping of the particle were evaluated with Thermo- Gravimetric Analysis TGA and had a residual mass of 25 % at 306 and#8451;. newlineThe Aspergillus trinidadensis capped GNPs have been demonstrated as an efficient heterogeneous catalyst AtGNHeC for the reduction of 4-Nitrophenol as a model substrate in water.