Oxygen permeability of nanocrystalline Ce0.8Gd0.2O1.9–CoFe2O4 mixed-conductive films
Isao Kagomiyaa, b, , , Takashi Iijimaa and Hitoshi Takamurac
aResearch Institute of Instrumentation Frontier, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568, Japan bCore Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), Tokyo 110-0015, Japan cDepartment of Materials Science, Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan
Received 11 November 2005; revised 9 September 2006; accepted 20 September 2006. Available online 24 September 2006.
Electronic and oxygen ionic conductive (mixed-conductive) oxides allow oxygen permeation under oxygen partial pressure differences at elevated temperatures of typically 800–1000 °C. The oxygen permeation performance decreases abruptly at lower temperatures as a result of the high activation energy required for solid-state transport of O2− ions and electrons. This study is intended to improve the oxygen permeation flux of a mixed-conductive solid oxide at lower temperatures. Dense nanocrystalline Ce0.8Gd0.2O1.9 (CGO)–CoFe2O4 (CFO) mixed-conductive films were prepared on porous Ce0.8Gd0.2O1.9 substrates using a chemical solution spin-coating technique. The oxygen permeation flux and morphology of the CGO–CFO films were investigated along with the crystallinity of the CGO–CFO powder samples. The oxygen permeation flux of the CGO–CFO films was improved through the use of a reduced preparation firing temperature, suggesting that the membrane's oxygen permeation properties are correlated closely with the material's nanocrystalline structure. This result is important for developing oxygen permeable devices with enhanced performance at lower temperatures of approximately 600 °C.