In this work; Cyclic-Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) were used to study the electrodeposition kinetic of selenium films in potentiostatic mode from aqueous solution containing selenium dioxide and sodium citrate at pH = 4.2. Semiconducting proprieties of obtained deposits were investigated by Mott-Schottky measurements whereas the optical ones were performed by UV-Visible spectrophotometry. The morphological characterization was carried out using the scanning electron microscopy (SEM). The obtained results showed that the electrodeposition process of selenium films in citrate bath occurred under diffusional regime as rate-limiting step. Deposition rate of selenium layers on platinum substrate is much superior than in the case of ITO substrate and up to a value of 0.65 μg/cm 2 s. The HSeO 3 − /Se system becomes more rapid with the increase of the bath temperature. Obtained deposits are photoactive films that belong to p-type semiconductors with number of charge carriers in order of 10 21 /cm 3 and energy band gap about 1.7 eV. The grains of electroplated films have spherical forms, nanometric sizes and strong adhesion on the substrate surface.
Electrochemical behavior of brass electrode (Cu-40Zn) in oxalic acid solution was studied in the absence and presence of organic inhibitor 2-Mercaptobenzimidazole (2-MBI) with different concentrations at ambient temperature using voltammetry, general corrosion (Rp) and electrochemical impedance spectroscopy (EIS). The results showed that the electrochemical behavior of brass surface is similar to the copper one in the same conditions and revealed also the absence of the complexity phenomenon between the brass and the oxalate. Evolution of abandonment potential presents two different behaviors of electrode surface according to the concentration of organic inhibitor (2-MBI). Polarization curves showed that the addition of organic inhibitor (2-MBI) decreases the current density and shifts the anodic and cathodic branches towards more positive and more negative potentials. The plot of C/θ against the inhibitor concentration (C) shows that (2-MBI) strongly physisorbed on the brass electrode according to Langmuir isotherm. Measurements of polarization resistance and impedances show that the optimal concentration of the inhibitor is (0.5 mM) which gives a protection rate exceeds 89%.
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