Synthesis of Palladium Nanoparticles by Sonochemical Reduction of Palladium(II) Nitrate in Aqueous Solution

Abstract

The sonochemical synthesis of stable palladium nanoparticles has been achieved by ultrasonic irradiation of palladium(II) nitrate solution. The starting solutions were prepared by the addition of different concentrations of palladium(II) nitrate in ethylene glycol and poly(vinylpyrrolidone) (PVP). The resulting mixtures were irradiated with ultrasonic 50 kHz waves in a glass vessel for 180 min. The UV-visible absorption spectroscopy and pH measurements revealed that the reduction of Pd(II) to metallic Pd has been successfully achieved and that the obtained suspensions have a long shelf life. The protective effect of PVP was studied using Fourier transform infrared (FT-IR) spectroscopy. It has been found that, in the presence of ethylene glycol, the stabilization of the nanoparticles results from the adsorption of the PVP chain on the palladium particle surface via the coordination of the PVP carbonyl group to the palladium atoms. The effect of the initial Pd(II) concentration on the Pd nanoparticle morphology has been investigated by transmission electron microscopy. It has been shown that the increase of the Pd(II)/PVP molar ratio from 0.13 x 10(-3) to 0.53 x 10(-3) decreases the number of palladium nanoparticles with a slight increase in particle size. For the highest Pd(II)/PVP value, 0.53 x 10(-3), the reduction reaction leads to the unexpected smallest nanoparticles in the form of aggregates.

Dielectric relaxation behavior of colloidal suspensions of palladium nanoparticle chains dispersed in PVP/EG solution

“…This is not surprising taking into account the following fact. On one hand, the Pd NP is surrounded by PVP molecules, which are absorbed by the surface via the coordination of the PVP carbonyl group to the Pd atoms, 38,39 therefore the diffusion of the ions within the double layer is blocked by PVP molecules and is slower than in bulk solution. On the other hand, since tangential counterion diffusion around the particle is forbidden as previously discussed, the volume diffusion mechanism proposed by Dukhin and Shilov 16 is preferable to account for the present dielectric relaxation, that is, the relaxation arises from the diffusion of ions in the bulk solution adjoining the EDL due to a concentration gradient, and D C is comparable to that in bulk solution.…”

Synthesis, characterization, and antimicrobial properties of copper nanoparticles

“…19 In general, quite a number of nanoparticles are prepared using polymer dispersions. [20][21][22][23] A number of techniques can be used to prepare copper nanoparticles, including thermal reduction, 24 a capping agent method, 25 sonochemical reduction, 26 metal vapor synthesis, 27 microemulsion techniques, 28 laser irradiation, 29 and induced radiation. 30 The present study investigated the antimicrobial properties of metallic copper nanoparticles synthesized in chitosan polymer medium through chemical means.…”

(Student Poster Award Winner) Sonochemical Preparation of PdCu as Oxygen Reduction NanoCatalyst for PEMFC

“…Radical species • H and secondary can act as reducing agents of metallic ions (12)(13)(14). In this work the following reactions are proposed for the sonochemical synthesis of PdCu:…”