The electrocatalytic effects in the electrolytic separation of hydrogen isotopes

Abstract

The electrolysis has been employed as one of the first and simplest methods for the prdouction of deuterium enriched water. The economical reasons mainly expressed through the energy consumption, however, reduced its importance and use on a large scale. Recent development in the field of the electrolysis, represented by the new electrode materials, different ionic activators for electrodes, generally in the field of the electrocatalysis, makes the electrolysis an interesting process now. A remarkable improvement of the separation factors of hydrogen isotopes during alkaline water electrolysis was achieved, in this work, with addition of tris(ethylenediamine) Co(III)-chloride complex into the electrolyte. Several spectroscopic and electrochemical methods like X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), IR and UV-VIS spectrophotometry and cyclic voltammetry, was employed to characterise the electrodes and electrolyte in order to suggest possible mechanisms and their contributions to the achieved separation factors. The overall mechanism which leads to the separation factor improvement in the presence of tris-Co complex includes different effects like decreases of the hydrogen overvoltage and the activation energies, with their specific contributions to the achieved factors.