Synthesis of Silver Nanoparticles by Microwave irradiation and investigation of their Catalytic activity

In this study, silver nanoparticles (AgNPs) have been synthesized in aqueous medium by a simple, efficient and economic microwave assisted synthetic route using hexamine as the reducing agent and the biopolymer pectin as stabilizer. The synthesized AgNPs were characterized by UV-vis. spectroscopy, Energy dispersive X-ray (EDX), X-ray diffraction (XRD) and Transmission electron microscopy (TEM) techniques. TEM images suggest that the nanoparticles are of spherical shape with an average diameter of 18.84 nm. The reduction of 4-nitrophenol to 4-aminophenol by NaBH 4 in aqueous medium was selected as a model reaction to investigate the catalytic activity of AgNPs. The pectin stabilized silver nanoparticles (AgNPpectin) were found to exhibit very good catalytic activity and the reaction followed pseudo-first order kinetics. The rate of reaction was found to increase with increasing temperature and the activation energy was found to be 47.3 kJ mol -1 .