Sonochemical Preparation of Single-Dispersion Metal Nanoparticles from Metal Salts

Novel metal nanoparticles of Pd and Pt were prepared by sonochemical reduction of solutions containing H 2 PtCl 6 or K 2 PdCl 4 . The effect of atmospheric gas on the particle size distribution was investigated. Average diameters and standard deviations of the Pd particles prepared under Ar (Pd/Ar) and N 2 (Pd/N 2 ) were found to be 3.6 ± 0.7 nm (Pd/Ar) and 2.0 ± 0.3 nm (Pd/N 2 ). Smaller and sharper distribution of the particle size was observed for the Pd particles formed under a N 2 atmosphere. In the case of Pt, a smaller and sharper distribution of the particle size was observed for the particles prepared under a Xe atmosphere. These relations can be explained in terms of a hot-spot temperature created by acoustic cavitation.