The paper presents the thermodynamic analysis of adenine adsorption on a mercury electrode in an acetate buffer at pH 3 and pH 4. Adsorption energy and constants were determined using the Frumkin isotherm and the virial isotherm. Stronger adsorption in the buffer at pH 3 was observed in comparison to the buffer at pH 4. Using cyclic voltammetry and Faraday impedance measurement, an inhibitory effect of adenine on the kinetics of Zn (II) ion electro-reduction was observed.

Adsorption of 1-decanesulfonic acid at the electrode–NaClO4 solution interface was determined by double-layer differential capacity measurements. At potentials less than −1,200 mV, the adsorption of the anionic surfactant on the electrode does not occur. Low concentrations of the anionic surfactant (below cmc) causes slight changes in the zero charge potential, Ez, and the surface tension at this potential, γz. The adsorption of the anionic surfactant was analyzed using the constants obtained from the following isotherms: Frumkin, corrected Flory–Huggins, and virial.Graphical Abstract

The kinetic parameters of Zn2+ ion electroreduction in sodium perchlorate used as the supporting electrolyte on the mercury electrode in the presence of methimazole were determined using electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and DC polarography. The two‐stage nature of this process was demonstrated. Both steps are catalysed by a methimazole. The size of the acceleration effect depends on the concentrations of methimazole and the supporting electrolyte. The acceleration of the electrode process involves the formation of active complexes between the depolarizer ions and methimazole on the electrode surface. These complexes facilitate the exchange of charge between the electrode and zinc ions during electroreduction process. The change of the hydrating sphere of the zinc ion is also important here. This in turn depends on its oxidation state and the concentration of the supporting electrolyte.

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