Initial stages of selenium electrodeposition onto glassy carbon electrode

Initial stages of selenium electrodeposition onto GC electrode were investigated in the sulphuric acid medium by means of cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The chronoamperometric results were shown to follow the progressive 3D nucleation and diffusion-controlled growth model by Scharifker and Hills. Electrochemical impedance spectroscopy investigations have revealed that the presence of a thin Se layer on the GC electrode does not change the inhomogeneity of the surface significantly, as the estimated values of the parameter n were very close for the bare GC and Se-modified GC electrodes and equal to similar to 0.9, but it affects the charge transfer rate at the applied E = 0.2 V. The estimated charge transfer resistance values for bare and selenium-covered GC electrodes differ markedly and range from 1 872 Omega cm(2) to 1 007 Omega cm(2), respectively. The obtained parameters of CPE capacitance and the ohmic resistance of the electrolyte solution for bare GC and Se-covered GC electrodes at the potential value E = 0.2 V are close and vary slightly, indicating that the structure of the double layer undergoes an insignificant alteration and the additional ohmic drop across the interfacial layer is negligible.