Oxygen surface exchange properties of La0.6Sr0.4Co0.8Fe0.2O3-δ coated with SmxCe1-xO2-δ

Chemical oxygen surface exchange coefficient (K-ex) Of La0.6Sr0.4Co0.8Fe0.2O3 - (delta) (LSCF) coated with samaria-doped ceria (SDC) particles has been investigated using the electrical conductivity relaxation method. It has been found that adding doped ceria to LSCF results in an increase of a factor of 10 in surface exchange rate, suggesting that oxygen incorporation at the LSCF/SDC/gas boundary sites is facile. Furthermore, K-ex of the SDC coated LSCF increases with the conductivity of SDC rather than the composition of the SDC, inferring that SDC supplies additional free oxygen vacancies for the surface exchange reaction. These results demonstrate that introducing doped ceria to La-1 - xSrxCo1 _ yFeyO3 - can substantially enhance the oxygen surface incorporation process for applications such as solid oxide fuel cell cathodes as well as oxygen separation membranes. (C) 2012 Elsevier B.V. All rights reserved.