Investigation of kinetics of the process of formation of gold and silver nanoparticles and composites based on them

This article is devoted to studying the kinetics of formation of individual nanoparticles of noble metals and composites based on them. The effect of the concentration of the reducing agent and temperature on the rate of formation of nanoparticles of noble metals is studied. In order to characterize the morphology, phase composition, and optical properties of the synthesized nanomaterials, X-ray diffraction, transmission electron microscopy, UV–visible spectroscopy, and Raman scattering (RS) are used. It is shown that the formation of nanoparticles of noble metals and composites based on them is a three-step process consisting of an induction period, the process of nucleation, and the particle growth stage (which has an autocatalytic character). The formed nanoparticles of noble metals catalyze the further process of reduction of ions remaining in the solution. It has been confirmed that an important factor for amplifying the signal from the analyte molecules in Raman spectroscopy is the resonance absorption by nanoparticles of noble metals in a wavelength range close to the wavelength of the excitation laser. © 2015, Pleiades Publishing, Ltd.