Hydrogen permeability in Ce0.8Yb0.2O1.9 at high temperatures

It was found that hydrogen permeated Ce0.8Yb0.2O1.9 (fluorite-type) at 1800–1000 K, which was sintered at 1970 K in air. The tube shaped two specimens were used to measure the hydrogen permeability, JH. Log(JH/mol h−1 cm−1) decreases with reducing temperature and is proportional to reverse temperature at 1800–1500, 1500–1300 and 1200–1000/K. The activation energies were 0.92±0.06, 1.10±0.06 and 0.58±0.05/eV, respectively. Ce0.8Yb0.2O1.9 would be an electron–proton mixed conductor under H2–H2O atmosphere at high temperature.