Investigation of hydrogen isotope behaviour in palladium membrane cathodes in the process of water electrolysis by the NERD method

Abstract

The elastic recoil detection technique with monochromatic 14-MeV neutrons (NERD) was applied for a hydrogen and deuterium concentration depth profile study in an electrolytic cell with a palladium membrane electrode. It was found that at ambient temperature the maximum H-content in a Pd membrane with its surfaces activated by Pd black depends on the current density, but does not exceed the value of 0.7 at% H/at% Pd while in a membrane without surface activation it is ∼ 0.82 at% H/at% Pd and does not change within the current density interval of 40–400 mA/sm2. In the case of isotope mixture water solution electrolysis, a higher H/D ratio was found at the electrolyte/membrane interface in comparison with that at zero current and a rather large isotope separation factor of (H/D)Pd/(H/D)sol ∼8 was measured.