A comparative study on the hydrogen dissolution and release behaviors in the zirconate proton conductors by TDS and TMAP4 analysis

Proton-conducting oxides are potential materials for electrochemical devices such as fuel cells, hydrogen pumps, hydrogen sensors, and the tritium purification and recovery system in nuclear fusion reactors. The hydrogen concentration in oxide materials is important, but its precise measurement is difficult. In this study, thermal desorption spectroscopy (TDS) was used to investigate hydrogen dissolution and release behavior in three zirconates, BaZr _0.9Y _0.1O _3-α (BZY), BaZr _0.955Y _0.03Co _0.015O _3-α (BZYC), and CaZr _0.9In _0.1O _2.95 (CZI) in the temperature range of 673–1273 K using deuterium (D ₂ ) (1.33 kPa) and heavy water (D ₂O) (2.8 kPa, saturated pressure at room temperature). To compare the experimental results of the D ₂ and D ₂ O desorption profiles derived by TDS analysis, the simulation code of the tritium migration analysis program, version 4 (TMAP4) was employed. From TDS measurement, a similar trend of temperature-dependent hydrogen solubility was obtained for all samples compared to the literature data of HT- and DTO-exposed samples using a tritium imaging plate (TIP) method. A higher amount of hydrogen was dissolved in both BZY and BZYC under D ₂ O exposure at 873 K, and the highest amount was found for BZYC. In most of the cases, the hydrogen diffusivities calculated by TMAP4 were higher than the experimental values, because oxygen is not considered a diffusion species in TMAP4.