Efficient and Environmentally Friendly Microwave-Assisted Synthesis of Catalytically Active Magnetic Metallic Ni Nanoparticles

Pure magnetic metallic nickel was synthesized by a simple and fast microwave-assisted method using a monomode microwave reactor. Nickel chloride was employed as metal precursor, while an environmental-friendly mixture of ethylene glycol and ethanol was simultaneously used as solvent and reducing agent. The parameters combination, for the occurrence of the reaction, of the mixture molar fraction, and the metal precursor concentration was developed. The influence of the temperature and the time of the irradiation was investigated. The best performance (71% yield) was achieved at 250 °C in 5 min of microwave irradiation. The phase and the morphology of the metal were analyzed by X-ray diffraction, scanning emission microscopy, and transmission electron microscopy, while the surface area was determined by nitrogen physisorption. The material exhibited a strong magnetic behavior. The metallic nickel showed high catalytic activity for the hydrogenolysis of benzyl phenyl ether, a lignin model compound, in a microwave-assisted environmental-friendly reaction.