Currently the development of modern chemistry occurs in several priority areas, one of which is the development and use technology based on transition metal nanoparticles. These derivatives are widely applied in modern industry. At the present time possibilities of using metal nanoparticles in creating the new catalysts for a variety of industrial processes grow extensively. So, cobalt nanosized particles occupy a special place among known metal nanoparticles as they allow to create the catalysts, magnetic recording devices, composites, carriers of biological products.
The majority of the methods of preparation of nanoparticles, especially physical methods, are energy consuming and require specialized equipment. Constraints of the methods related to difficulties in controlling the chemical composition of product, contamination of metal nanoparticles by initial reactants. Therefore, the development of research in this area requires new methods of preparation of nanoparticles. One perspective direction is an electrochemical method for the selectively generation of metal nanoparticles of a certain size with desired properties and catalytic activity.
We have found that electrochemical reduction of coordinatively unsaturated cobalt dibromide 2,2’-bipyridine (bpy) complexes results in the formation of cobalt nanoparticles (CoNPs).4 The process of the electrochemical generation of CoNPs was monitored by in situ EPR-spectroelectrochemistry where the signals of ferromagnetic resonance (FMR) have been observed for these species. According to small-angle X-ray scattering (SAXS) analysis the average diameter and average length of the formed cylindrical CoNP is varied from 9 to 10 nm and 30-32 nm, respectively, and correlates to the g-value and the broadness of the FMR signal observed by in situ EPR-spectroelectrochemistry during the electrochemical process.