A simple approach for the synthesis of silver nanoparticles and their application as a catalyst for the photodegradation of methyl violet 6B dye under solar irradiation

In the present study, we established for the first time a simple method for the preparation of silver nanoparticles (Ag NPs) using saturated fatty acid and tryptophan as capping and reducing agent, respectively. The -NH2 group of tryptophan and the carboxylate group of saturated long chain carboxylate endow them as reducing and stabilising property respectively. The -NH2 group of the tryptophan reduced the Ag+ ions while the carboxylate group bounded strongly to the surface of the nanoparticles (NPs). This approach is a very special, size controlled synthetic approach for the large-scale synthesis of Ag NPs. The sizes of the synthesised Ag NPs were controlled by varying the processing parameters, such as reaction time and the chain length of the silver carboxylate (C12–C16). Studies showed that the particle size of Ag NPs increases with increase in reaction time and carbon chain length. The synthesised Ag NPs were characterized by ultra-violet spectroscopy (UV–vis), transmission electron spectroscopy (TEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD). The synthesised Ag NPs was used to evaluate the photo catalytic degradation of the methyl violet 6B dye under solar irradiation. The efficiency and rate of photo degradation of methyl violet 6B dye were also studied.