Synthesis, characterization and magnetism of monodispersed water soluble palladium nanoparticles

Water soluble, monodispersed Pd nanoparticles with a narrow particle size distribution have been successfully synthesized by controlled reduction of [PdCl4](2-). The resulting aqueous colloids are stable over extended periods of time and can be prepared at high nanoparticle loading (20 g/L of Pd) with no agglomeration. The size of the nanoparticles can be reduced from the nanometer (ca. 3.5 nm) to the sub- nanometer size range (ca. 0.9 nm). Detailed magnetic characterization indicated that the larger, 3.5 nm nanoparticles show ferromagnetic properties at room temperature, while the sub- nanometric ones lose this magnetic behavior.