Content area
Full Text
ABSTRACT
Kinetics of the reaction of silver nitrate reduction by hydrazine in the presence of sodium citrate in alkaline medium was studied in a wide range of the reagents concentration variation. The orders of the reaction were determined and the effective constants of the silver nanoparticles nucleation process rate and of their propagation one were calculated. It was investigated the optical characteristics of the obtained sols of the silver nanoparticles. It was determined the empirical dependence of a size of the obtained silver nanoparticles on the kinetic parameters of a process.
Keywords: silver nanoparticles, nucleation, nanoparticles growth, kinetics
(ProQuest: ... denotes formulae omitted.)
1. INTRODUCTION
An exponential growth in a field of the fundamental and applied sciences connected with a synthesis of the nanoparticles of noble metals, studies of their properties and practical application is observed for the last decades. Silver nanoparticles (Ag-NPs) are characterized by unique combination of the important physical-chemical properties, namely by excellent optical characteristics caused by the phenomena of the surface plasmon resonance [1], by ability to amplify the signal in spectroscopy of the combination dispersion and also by high antibacterial properties. Despite the fact, that there are a number of methods for the synthesis of different upon nature nanoparticles and nanomaterials describing in references [2-7], however the kinetic peculiarities and regularities of the formation (nucleation and propagation) of nanoparticles studied insufficiently and has the episodical character [8-10].
That is why the aim of the presented work was to investigate an influence of the synthesis conditions on the kinetic parameters of a process and also on the form and on the size of the synthesized Ag-NPs.
2. EXPERIMENTAL SECTION
Ag-NPs were obtained in accordance with the reaction (1) via reduction of silver nitrate by hydrazine in aqueous medium in the presence of sodium hydroxide at 20 0C:
... (1)
Sodium citrate has been used as the stabilizer at its concentration 1×10-4 mole/l in the reactive solution.
Kinetic of the reaction was studied by direct potentiometry method with the use of the ion-selective microelectrode «ELIS-131 Silver». The concentration of the silver ions was determined continuously during the reaction proceeding per change of the potential of the ion-selective electrode regarding to the chlorine-silver comparison electrode. In order to avoid the hit of...