Hydrogen isotope absorption and separation by palladium and palladium alloys

Abstract

Information concerning the interrelationships between the contents and the chemical potentials of hydrogen isotopes in palladium and palladium alloys can prove useful for assessing the relative importance of intermediate kinetic steps in studies of hydrogen isotope separation effects during electrolytic discharge. Further useful experimental advantages of palladium and palladium alloy electrodes for this area of study are the high solubilities and high mobilities of the hydrogen isotopes and the possibility of continuous monitoring of hydrogen contents by measurements of physical properties such as electrical resistance. These features make it conveniently possible to calculate the efficiency of absorption of electrolytically discharged hydrogen isotopes by the electrodes and to estimate the relative importance of desorption and absorption of isotope molecules to and from the surrounding electrolytic solution. They can also be used to provide information concerning the catalytic activity of the electrode surface for exchange of adsorbed isotope atoms with the electrolytic solution. Results of series of studies with variously activated surfaces, of electrolytic isotope separation and of the activity of surfaces for isotope exchange with the solution, have indicated a significant need, in both types of measurements, for considering the effects of local-cell hydrogen transfer between surface regions of differing electrode potentials.