Size-controlled reverse microemulsion synthesis of Ni and Co metal nanoparticles

Microemulsion synthesis of Ni and Co metal nanoparticles with controllable size has been studied in detail to allow replacing expensive metals (Pt and Re) in promising aqueous phase reforming of bio-derivatives. Reduction of nickel or cobalt chloride and nitrate aqueous solutions with N2H4 alkaline solution in the presence of cationic cetyltrimethyl bromide or anionic sodium dodecylsulphosuccinate surfactants provided formation of series of Ni and Co nanoparticles with mean sizes from 2.6 to 3.3 nm and from 1.0 to 5.4 nm, respectively. TEM, XRD, UV-Vis spectroscopy and XPS were applied to determine Ni and Co nanocluster sizes, composition and electronic state.