Oxygen transport in Ce0.8Gd0.2O2-delta-based composite membranes
authors Kharton, VV; Kovalevsky, AV; Viskup, AP; Shaula, AL; Figueiredo, FM; Naumovich, EN; Marques, FMB
nationality International
journal SOLID STATE IONICS
author keywords composite; ceria; perovskite; membrane; oxygen permeation
keywords FORMER SOVIET-UNION; IONIC-ELECTRONIC CONDUCTION; PR-DOPED CE(GD)O2-DELTA; OXIDE FUEL-CELLS; ELECTRICAL-PROPERTIES; SEPARATION MEMBRANES; ELECTROCHEMISTRY; PEROVSKITES; CERIA; PERMEABILITY
abstract Gadolinia-doped ceria electrolyte Ce0.8W0.2O2-delta (CGO) and perovskite-type mixed conductor La0.8Sr0.2Fe0.8XCo0.2O3-delta (LSFC), having compatible thermal expansion coefficients (TECs), were combined in dual-phase ceramic membranes for oxygen separation. Oxygen permeability of both LSFC and composite LSFC/CGO membranes at 970-1220 K was found to be limited by the bulk ambipolar conductivity. LSFC exhibits a relatively low ionic conductivity and high activation energy for ionic transport (similar to 200 kJ/mol) in comparison with doped ceria. As a result, oxygen permeation through LSFC/CGO composite membranes, containing similar volume fractions of the phases, is determined by the ionic transport in CGO. The permeation fluxes through LSFC/CGO and La0.7Sr0.3MnO3-delta/Ce0.8Gd0.2O2-delta (LSM/CGO) composites have comparable values. An increase in the p-type electronic conductivity of ceria in oxidizing conditions, which can be achieved by co-doping with variable-valence metal cations, such as Pr, leads to a greater permeability. The oxygen ionic conductivity of the composites consisting of CGO and perovskite oxides depends strongly of processing conditions, decreasing with interdiffusion of the phase components, particularly lanthanum and strontium cations from the perovskite into the CGO phase. (C) 2003 Elsevier Science B.V. All rights reserved.
publisher ELSEVIER SCIENCE BV
issn 0167-2738
year published 2003
volume 160
issue 3-4
beginning page 247
ending page 258
digital object identifier (doi) 10.1016/S0167-2738(03)00183-8
web of science category Chemistry, Physical; Physics, Condensed Matter
subject category Chemistry; Physics
unique article identifier WOS:000184677700005
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journal impact factor 3.107
5 year journal impact factor 2.904
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