Microwave-assisted green synthesis of Gold nanoparticles and Its catalytic activity

The present work demonstrated a green approach of synthesis of gold nanoparticles using Eupatorium odoratum leaf extract as reducing and stabilizing agent assisted with microwave irradiation. Effects of various concentrations of leaf extract on the preparation of gold nanoparticles have been investigated and it was monitored by undertaking UV-vis spectroscopic studies. The experimental results showed that the surface Plasmon resonance (SPR) peak blue shifted with increase in the concentration of leaf extract indicating the decrease of nanoparticles size, which was further confirmed by the Dynamic light scattering (DLS) data. Synthesized particles were further characterized by Fourier Transform Infra-Red spectroscopy (FTIR) and Transmission Electron Microscopy (TEM). All the characterization results confirmed the formation of stable spherical mono-dispersed gold nanoparticles with size ranging from 10-20 nm. The catalytic activity of prepared gold nanoparticles was checked by reducing Nitrophenol to Aminophenol in presence of an excess amount of sodium borohydride. The progress of the reaction was examined by observing the absorbance peak of UV-vis spectroscopy. The study showed positive results and it was found that gold nanoparticles synthesized with 600 μL leaf extract have greater catalytic activity. It was also found that gold nanoparticles remained stable for long duration of time.