Electrochemical analysis of co-deposition cobalt and selenium

The work describes the process of electrochemical synthesis of cobalt selenide from aqueous solutions. The mechanism of co-deposition of selenium with cobalt was examined with the method of the cyclic voltammetry and rotating disk electrode. The tests were conducted in acid solutions of pH = 2 applying different concentrations of cobalt(II) sulphate(VI) and selenous acid(IV). On the basis of the results obtained during electroanalytical tests a range of potentials where co-deposition of selenium and cobalt takes place was determined. Next, the results were confirmed conducting a process of depositing the coatings in potentiostatic conditions on a gold electrode and a copper one. The X-ray fluorescence was used to test the elemental composition of the deposited coatings from solutions containing different concentrations of selenous acid(IV). The phase analysis indicated presence of a phase mixture of CoSe and Co9Se8 in the coating. An influence of the applied potential and concentration of the electrolyte components on the coatings morphology was defined with the use of the scanning electron microscopy.