Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Overall anodic polarization curves and partial polarization curves of oxygen evolution and formation of peroxosulphates (S₂O₈^2- + SO₅^2-) were measured potentiostatically on a smooth platinum anode in 1-13M-H₂SO₄ at 25 °C at a small degree of conversion of SO₄^2- to S₂O₈^2- ions. The known dependences of the current yield of peroxodisulphate on the total concentration of sulphuric acid at various current densities were substantiated. The found results were used to explain mechanism of formation of S₂O₈^2- ions, according to which in contrast to previous explanations the possibility of simultaneous discharging of SO₄^2- and HSO₄^- ions is considered with partial rates depending on the reaction conditions. A mathematical formulation of this mechanism is in qualitative agreement with experiments, an evidence for the probability of the mechanism. A correlation of the current yield with the actual concentrations of SO₄^2- and HSO₄^- ions at various temperatures helps to further elucidate the negative influence of the temperature on the current yield.