Sonochemical synthesis of palladium nanoparticles and its electrocatalytic activity for oxidation of formic acid

Monodispersed palladium nanoparticles have been synthesized from palladium(II) chloride aqueous solution by ultrasonication without gas protection and in the absence of an external reducing agent, by the addition of a small quantity of polyvinylpyrrolidone (PVP). The monodispersity and columnar crystallinity of palladium nanoparticles have been observed using TEM and HRTEM respectively. The five X-ray diffraction peaks of the metallic Pd indicated that Pd(II) ions have been reduced to palladium atoms Pd(0). The formation of nanoparticles has been investigated using FT-IR spectroscopy. Results show that the PVP can protect metal nanoparticles via the coordination of the PVP carbonyl group to the palladium atoms and the steric effect of the PVP polymer long chain. The activity towards formic acid oxidation reaction (FAOR) has also been measured.