A modified electroless route to monodisperse and uniform nickel nanoparticle

Monodisperse and uniform nickel nanoparticles with an average diameter of ∼30 nm were synthesized through a modified electroless route in which nickel hydroxide (Ni(OH)2) colloid, H2O/ethylene glycol (EG) mixing solution, and sodium hypophosphite were used as Ni source, solvent, and reducing agent, respectively. Different from the conventional electroless process, only a trace concentration of complexing agent, ethylenediaminetetraacetic acid (EDTA), was used in this route. At the optimum H2O/EG volume ratio, monodisperse nickel nanoparticles of high crystallinity were obtained. The presence of trace concentrations of EDTA is necessary for uniformity of the synthesized nickel nanoparticles. The formation process is discussed based on the experimental results.