Ion Transfer during the Electrochemical Reduction of Oxygen on Copper–Ion Exchange Nanocomposites

Abstract

The electrochemical reduction of oxygen dissolved in water is studied using a thin granular layer of nanocomposites of copper–sulfonic acid cation exchanger in different ionic forms (H+, Na+). It is established there is considerable acceleration of oxygen absorption in the initial period under the simultaneous impact of electrical polarization and chemical activity of nanocomposites, especially in the H+-form. The rate of the process later slows and reaches a constant value regardless of the ionic form of the nanocomposite and without changing the pH or electrical conductivity of water. Products of the oxidation of metal nanoparticles form as insular nuclei distributed over the volume of nanocomposite granules; some grains are oxidized with the formation of sharp boundaries of oxide layers. A stationary mode of oxygen absorption is established due to the constant generation of hydrogen ions required for the reaction on anodes and the regeneration of copper nanoparticles on cathodes. It is concluded that these patterns are based on conjugate processes of ion transfer, electrochemical and chemical oxygen reduction, and the oxidation and reduction of copper nanoparticles.