It was found that H permeated through fluorite-type Ce0.8Yb0.2O1.9, which had been sintered at 1970K in air, at 1000 to 1800K. Two tube-shaped specimens were used to measure the H permeability. The logarithm of the permeability decreased with decreasing temperature, and was proportional to the reciprocal of the temperature at 1500 to 1800, 1300 to 1500 and 1000 to 1200K. The corresponding activation energies were 0.92, 1.10 and 0.58eV, respectively. The Ce0.8Yb0.2O1.9 was expected to be an electron-proton mixed conductor in a H2-H2O atmosphere at high temperatures.

Hydrogen Permeability in Ce0.8Yb0.2O1.9 at High Temperatures. Y.Nigara, K.Kawamura, T.Kawada, J.Mizusaki: Solid State Ionics, 2000, 136-137, 215-21