Water incorporation studies on doped barium cerate perovskites

BaCeO3-based perovskites exhibit high proton conductivities and are attractive candidates for application in electrocatalysis and fuel cells. In BaCe1-xYxO3-x/2, 0 less than or equal to x less than or equal to 0.15, the degree of hydration is directly related to the oxygen vacancy concentration and increases linearly with dopant content, x. The water content of the material depends predominantly on the number of oxygen vacancies. At maximum hydration, ca. 80% of oxygen vacancies are filled. The loss of water is primarily dependent upon temperature, with water loss occurring over a range of similar to200 degreesC. Samples with higher oxygen vacancy contents retain more water at high temperatures, and hence probably also have higher proton transport numbers at high temperatures. Under reducing conditions, water loss is accompanied by oxygen loss. (C) 2003 Elsevier B.V. All rights reserved.