Please use this identifier to cite or link to this item:
http://hdl.handle.net/10773/21987
Title: | Oxygen transport in Ce0.8Gd0.2O2 - δ-based composite membranes |
Author: | Kharton, V.V. Kovalevsky, A.V. Viskup, A.P. Shaula, A.L. Figueiredo, F.M. Naumovich, E.N. Marques, F.M.B. |
Keywords: | Ceria Composite Membrane Oxygen permeation Perovskite Activation energy Composite materials Doping (additives) Electric conductivity Electric conductors Interdiffusion (solids) Membranes Oxygen Perovskite Positive ions Thermal expansion Volume fraction Oxygen transport Cerium compounds |
Issue Date: | Jun-2003 |
Publisher: | Elsevier |
Abstract: | Gadolinia-doped ceria electrolyte Ce0.8Gd0.2O2 - δ (CGO) and perovskite-type mixed conductor La0.8Sr0.2Fe0.8Co0.2O3 - δ (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 (∼ 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 - δ/Ce0.8Gd0.2O2 - δ (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. |
Peer review: | yes |
URI: | http://hdl.handle.net/10773/21987 |
DOI: | 10.1016/S0167-2738(03)00183-8 |
ISSN: | 0167-2738 |
Appears in Collections: | CICECO - Artigos |
Files in This Item:
File | Description | Size | Format | |
---|---|---|---|---|
SSI160_247.pdf | Article | 584.95 kB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.