Oxygen permeability in ZrO 2TiO 2Y 2O 3 system

Abstract

The oxygen permeability of yttria-stabilized zirconia containing 7.5 and 10 mol% TiO 2 was measured under low oxygen partial pressure and at high temperatures up to 1500°C. The measured oxygen permeability increases with decreasing oxygen partial pressure according to P −1/6 O 2 . This proportionality indicates that the n-type electronic conduction in the yttria-stabilized zirconia containing TiO 2 is due to the electron hopping between Ti 4+ and Ti 3+ ions. The activation energy of 1.9 eV is obtained for the electronic conduction. At 1000°C, the contribution of the electronic conduction is negligibly small even under low oxygen partial pressure. From these results, ZrO 2TiO 2Y 2O 3 system is not so promising materials for electrode in SOFC. As this system is stable and has a high oxygen permeability at high temperatures up to 2000°C, it is the promising material as a membrane for a direct water splitting at high temperatures to produce hydrogen.