Microwave-assisted synthesis of nickel nanoparticles

Nickel nanoparticles with uniform, monomorphic self-assembled flower-like microstructure were synthesized by reduction of nickel chloride with hydrazine hydrate in the presence of polyvinylpyrrolidone (PVP) in ethylene glycol under microwave irradiation. An appropriate amount of Na₂CO₃ was necessary for the formation of monomorphic and uniform Ni nanoflowers. Small amount of NaOH and a higher concentration of hydrazine were beneficial to the formation of Ni nanoflowers with a smaller diameter and a narrower distribution. The transmission electron microscopy (TEM) and X-ray diffraction measurements manifested that the as-synthesized Ni nanoflower was the assembles self-organized by hundreds of smaller primary nanoparticles with an average dimension of about 6.3 nm.