Isotopic effect of proton conductivity in gadolinium sesquioxide

Abstract Due to the higher hydrogen solubility and diffusivity, gadolinium sesquioxide (Gd2O3) could be expected as a proton conductive material. In this study, monoclinic Gd2O3 was used to evaluate the possible proton conductivity in Ar ( σ Ar ), Ar+4% H2 ( σ H 2 ), Ar+4% D2 ( σ D 2 ), Ar+H2O ( σ H 2 O ), Ar+D2O ( σ D 2 O ), and O2 ( σ O 2 ) atmospheres in the temperature range from 500°C to 1000°C, to understand its possible application in the DT fuel system of a nuclear fusion reactor. At all temperatures, the conductivity σ D 2 was lower than that of the σ H 2 . Similarly, the σ D 2 O was always lower than that of the σ H 2 O . The isotope dependence was appreciable at higher temperatures, indicating that Gd2O3 is a proton-conductive oxide at elevated temperatures. However, much improvement is required for the use of Gd2O3 in the DT fuel recovery, analysis, and purification system of fusion reactors.