Electrochemical impedance of platinum in concentrated chloride solutions under potentiodynamic anodic polarization: Effect of alkali metal cations

Potentiodynamic electrochemical impedance spectroscopy has been applied to examine cation specific effects in anodic behaviour of platinum in 3 M aqueous solutions of LiCl, NaCl, KCl and CsCl. Double layer capacitance was slowly varying with potential between “double layer” region and platinum anodic dissolution and chlorine evolution, and this provided a convenient background for examination of the complementary part of the potentiodynamic ac response which disclosed strong cation effect in the variation with potential of charge transfer resistance and parameters of equivalent circuit that represented interactions beyond the double layer.