The electrocatalytic effects in the electrolytic separation of hydrogen isotopes

The electrolysis has been employed as one of the first and simplest methods for the production 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 electro chemical methods like X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron on 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 lends to the separation, factor improvement in the presence of trs-Co complex includes different effects like decreases of the hydrogen overvoltage and the activation energies, with their specific contributions to the achieved factors.5th International Symposium on Advances in Electrochemical Science and Technology, Nov 24-26, 1994, Madras, Indi

A Comparison of Alkaline and Proton Exchange Membrane Electrolyzers

Faraday efficiencies and energy consumptions of a small commercial proton exchange membrane (PEM) and an alkaline electrolyzer designed at our laboratory and equipped with different cathode materials were determined. Our experimental data indicate that the alkaline electrolyzer has a higher Faraday efficiency than the PEM electrolyzer, but, on the other hand, less energy is required for the PEM electrolyzer compared with the alkaline one. The results are discussed with regard to the special advantages of electrolyzers of both types

Influence of magnetic behavior of cathodic surface on deuterium separation factor

The influence of magnetic properties of cathodes on the separation factor and hydrogen evolution process was investigated. The cathodes used in standard electrolyte and in activated one were pure Ni and the electrocatalytic coatings with definite compositions of transition metals on Ni substrate. The obtained correlations between electrocatalytic activity and magnetic properties of the investigated cathode materials issue from their d-electronic configuration. (c) 2007 Elsevier B.V. All rights reserved

Hydrogen production and storage-Investigation of Hf-based intermetallics

Hafnium-based interriletallics Hf(2)Fe, Hf(2)Co and Hf(2)Ni are investigated as hydrogen absorbers at atmospheric pressure and their electrocatalytic activities are compared. The absorption process is carried out in typical volumetric apparatus. Their crystal structures and morphological characteristics are investigated by X-ray difractometry (XRD) and scanning electron microscopy (SEM). According to the absorption abilities, the investigated intermetallics can be ordered as follows: Hf(2)Fe GT Hf(2)Co GT Hf(2)Ni. Ab initio calculations, within the framework of the density functional theory (DIFT), as implemented in the full-potential (linearized) augmented plane-wave (FP/LAPW) method, confirms the experimental investigations. The calculations are important as a way of predicting the best cathode and storage materials. (C) 2009 Elsevier B.V. All rights reserved