Electrical Double Layer on Liquid Bi–Ga Alloys in Aqueous Solutions

Abstract

Double-layer characteristics of a liquid bismuth–gallium electrode are studied in aqueous electrolyte solutions. Based on the results obtained it is shown that Bi in an alloy with Ga is a surface-active component and forced out to the electrode surface layer. For electrode charges q ≤ –5 μC/cm2, the double layer characteristics of Bi–Ga electrodes approach those of a bismuth electrode. Thus, with respect to its electrochemical properties, a Bi–Ga electrode containing 0.25 at. % Bi simulates a liquid bismuth electrode. The “corrected electrochemical work function” is determined for bismuth. The close values of the difference of zero-charge potentials on mercury and bismuth in water and the difference of “corrected electrochemical work functions” for these metals points to the very low hydrophilicity of the Bi–Ga electrode, which approaches the value for mercury at negative electrode potentials. Taking into account that the Bi–Ga electrode displays no semimetallic properties, the similarity of the electric double layer (EDL) parameters for the Bi–Ga alloy and solid pure Bi indicates that the semimetallic properties of bismuth make no contribution to the EDL characteristics of the alloy in the studied range of negative charges q ≤ –5 μC/cm2.