N. Ivanova

Electrochemical Synthesis of Black Cobalt

The possibility of depositing black cobalt coatings from fluoride-containing electrolytes based on cobalt sulfate was studied.

Li+-Doping-Induced Changes of Phase Composition in Electrodeposited Manganese(IV) Oxide Materials

The impact of Li+ dopant-ions in fluorine-containing electrolytes on electrodeposited manganese (IV) oxide material was under investigation in this paper. The dependence of phase composition of this material at Li+-concentration range in the electrolyte below the stoichiometric content of lithium in hollandite A2Mn8O16 (Mn:Li ≈ 4:1) was established. The hollandite phase stabilization as a template effect caused by Li+-ions is gradually reduced with the Li+ concentration growth from 0.025 to 0.15mol∙L-1 LiOH concentration range. The hollandite content sharply drops at close to the stoichiometric Mn:Li ratio for the hollandite phase. In contrary, the concentration of cation-deficient ε-MnO2 becomes significant. Thus, the template effect of Li+ cations at electrolytic doping from fluorine-containing electrolytes consists of stabilization of the hollandite tunnels at longer distance with the size of coherent scattering regions of this phase more than of about 20—50 Å comparing with undoped materials. It is supposed that Li+-ions presence makes tunnel space unavailable unlike water molecules or ammonium cations. Therefore, to realise molecular sieves based on manganese (IV) oxides the availability of tunnels should be taken into account.

Kinetics of electrooxidation of Co(II) ions in a fluorine-containing electrolyte

The electrochemical oxidation of Co(II) ions in fluorine-containing electrolytes on stationary and rotating disc electrodes was studied.