Isotopic effect of proton conductivity in barium zirconates for various hydrogen-containing atmospheres.

• Conductivity of BZY and BZYC was investigated in six H-atmospheres including D 2 and D 2 O. • Cobalt not only improves the sinterability but also improves the conductivity at 500–800 °C. • Isotopic dependency was confirmed both in the dry and wet hydrogen atmospheres. [Display omitted] Among various perovskite proton conducting oxides, Y-doped BaZrO 3 perovskite is a promising material for electrochemical hydrogen devices due to its good chemical stability and higher proton conductivity at higher operating temperatures like 500–800 °C. For the practical application of the functional BaZrO 3 proton conductors in electrochemical hydrogen devices like tritium purification and recovery systems in a nuclear fusion reactor (where deuterium and tritium isotopes are utilized as fuel), it's necessary to understand the isotopic effect of proton conductivity. To understand the isotopic effect of proton conductivity in the barium zirconates, in this study, the proton conductivities in the Ar, (Ar + 4% H 2), (Ar + 4% D 2), (Ar + H 2 O), (Ar + D 2 O), and O 2 atmospheres were measured for two different compositions: BaZr 0.9 Y 0.1 O 2.95 (BZY), and BaZr 0.955 Y 0.03 Co 0.015 O 2.97 (BZYC) in the temperature range from 500 °C to 1000 °C. By comparing the obtained results, a significant difference in sinterability, conductivity, and the isotopic effect was observed due to the co-doping of the Co element in the BaZr 1−x Y x O 3-α proton conductor. [ABSTRACT FROM AUTHOR]