PVP Protective mechanism of palladium nanoparticles obtained by sonochemical process

The protective effect of polyvinylpyrrolidone (PVP) on the palladium nanoparticles has been investigated using Fourier Transform Infrared Spectroscopy (FT-IR). Palladium nanoparticles have been obtained by ultrasonic irradiation of Pd(NO3)2 solution in presence of ethylene glycol (EG) and PVP. The sonochemical reduction process of palladium ions (Pd(II)) to palladium atoms (Pd(0)) can be explained by considering the intense ultrasonic waves that are strong enough to produce cavitation: formation, growth and collapse of bubbles. The UV-Visible absorption spectroscopy revealed that the reduction of Pd (II) to metallic Pd has been successfully achieved. The FT-IR spectroscopy spectra analysis show that, in 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 transmission electron microscopy (HRTEM) and electrondispersive X-ray (EDX) results confirm the dispersion, the nanometric size and the composition of the obtained palladium particles.