Size-controlled synthesis of palladium nanoparticles

Palladium nanoparticles protected by PVP were obtained first by reducing PdCl2 with NaBH4 solution. Then different size palladium nanoparticles with a large size range (1.49 nm similar to 23.26 nm) were prepared by the multi-step reduction of PdCl2 by hydrogen adsorbed on the surface of palladium nanoparticles. Transmission electron microscopy (TEM) and x-ray diffraction (XRD) were used to characterize the nanoparticles. The increasing value of average diameter from the first to the eighth reduction reaction is about 0.58 nm, from the ninth to the fifteenth reduction reaction the value is about 2.44 nm.