Proton concentration in 15 mol% Y-doped BaZrO₃ proton conductors prepared at various temperatures

Proton concentration as a function of ambient temperature in 15 mol% Y-doped BaZrO₃ proton conductors prepared at 1800 °C, 1600 °C and 1400 °C, is measured by thermo-gravimetric (TG) analysis. TG analysis reveals that the maximum proton concentration in the specimen prepared at 1400 °C is over 15 mol%. The value is over the limitation decided by hydration process via oxygen vacancy. Infrared diffuse reflection spectroscopy confirms that additional O-D stretching vibration exists in the specimen. Both results strongly suggest that not a few amounts of water incorporate in the specimen prepared at low temperature through other hydration process.