| Dispersed and aggregated palladium nanoparticles have been obtained by ultrasonic irradiation of Pd(NO3)2 solution in presence of ethylene glycol and polyvinylpyrrolidone (PVP). The UV-Visible absorption analyses confirm the dependence of the sonochemical reduction of palladium(II) ions to palladium(0) atoms with increasing sonication time. The transmission electron microscopy micrographs show that, for the high presence of PVP, the sonochemical reduction of palladium ions leads to the formation of monodispersed palladium particles having a rounded shape and a mean diameter of about 5 nm. The use of a low quantity of PVP involves the obtaining of aggregates palladium nanoparticles. The dynamic light scattering measurements reveal that the palladium nanoparticles aggregates have a large size distribution centered at 20 nm. |
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