Electrochemical Activity of Metal-Ion Exchanger Nanocomposites

Resumo

The electroreduction of oxygen on thin-film metal–polymer nanocomposites that differ in the metal (Ag, Cu, Pd), content, particle size of the metal component, and ionic form of the Lewatit K2620 matrix (H⁺, Na⁺) was studied. The limiting oxygen diffusion current and effective number of electrons involved in oxygen electroreduction were determined. The limiting current and the number of electrons increased with the content of metal nanoparticles and transition to larger nanoparticles. The oxygen electroreduction occurs by the four-electron mechanism, whereby the hydrogen peroxide intermediate product does not accumulate, and oxygen is reduced directly to water molecules. The electrochemical reduction of the metal oxidation products and hydrogen evolution can be observed depending on the ionic form of the matrix.