Influence of sodium 1-decanesulfonate on the enthalpy of activation of two-step Zn2+ ions electroreduction

The results of measurements carried out at different temperatures concerning the kinetic process of the electroreduction of Zn2+ ions on mercury electrode in the presence of sodium 1-decanesulfonate showed the two-step character of the electrode process and accelerating influence of sodium 1-decanesulfonate on the rate of Zn2+ electroreduction of the investigated systems. The values of rate constants as determined for successive steps in the investigated temperature range provided evidence that the transfer of the first electron is the step which determines the rate of the whole process. The catalytic activity of sodium 1-decanesulfonate was confirmed by the decrease of overall enthalpies of activation which means the decrease of the activation barrier of the first electron transfer. In order to better understand the mechanism of Zn2+ ions electroreduction in the presence of sodium 1-decanesulfonate the IE and IA mechanisms are discussed.

► Different mechanistic schemes assuming two-step character of Zn2+ electroreduction are discussed.
► The increase of anionic detergent concentration move Zn2+ ion closer to the electrode surface.
► The rate constants of Zn2+ electroreduction increase in the presence of sodium 1-decanesulfonate.
► The values of the enthalpies of activation of Zn2+ confirm the catalytic activity of sodium 1-decanesulfonate.