The cobaltnanoparticles synthesizedinthis work wereprepared
by chemical reduction of CoCl2 in water using NaBH4 as reducing
agent and PVP as stabilizer (Scheme 2). The TEM micrographs
and size histograms of Co1-4 are displayed in Fig. 1. According to
TEM analysis, spherical cobalt nanoparticles of diameters between
1.7–7.0 nm were obtained. As a general trend, it was observed that
increasing the concentrations of both NaBH4 and CoCl2/PVP solutions,
resulted in a decrease of the CoNPs size