Original scientific paper

Formation and Stabilization of Noble Metal Nanoparticles

Szilvia Papp ; Nanostructured Materials Research Group of the Hungarian Academy of Sciences, Szeged, Hungary
Rita Patakfalvi ; Nanostructured Materials Research Group of the Hungarian Academy of Sciences, Szeged, Hungary
Imre Dékány ; Nanostructured Materials Research Group of the Hungarian Academy of Sciences, Szeged, Hungary; Department of Colloid Chemistry University of Szeged, Szeged, Hungary

Abstract

The kinetics of homogeneous and heterogeneous nucleation processes of metal (Ag, Pd) nanoparticles
was studied by UV-VIS spectrometry. Silver nanoparticles were prepared in aqueous
solution by homogeneous nucleation using poly(vinylpyrrolidone) (PVP) and sodium citrate as
sterical stabilizers. Reduction was ensured by adding hydroquinone. According to kinetic functions,
reduction is an autocatalytic process: a slow, continuous nucleation is followed by a fast,
autocatalytic growth. The presence of polymer inhibits nucleation and retards the rate of particle
growth. Formation of palladium nanoparticles was investigated in aqueous medium via reduction
by hydrazine, using PVP and the clay mineral hectorite as stabilizers. Effects of the
polymer and concentration of silicate and palladium ions on the particle formation rate were
analyzed. The rate of reduction is decreased by increasing amounts of stabilizing agents and increased
by increasing concentrations of precursor ions. The kinetics of heterogeneous nucleation
was determined based on the adsorption of the palladium species at the clay mineral particles
and the viscosity of the hectorite dispersion.

Keywords

palladium; silver; nanoparticle formation; UV-VIS spectroscopy; TEM

Hrčak ID:

18673

URI

https://hrcak.srce.hr/18673

Publication date:

30.11.2007.

Visits: 7.114 *