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Ca substitution in Ca1‐xSrxTi0.8Fe0.2O3‐δ perovskites for oxygen transport membranes: A promising strategy to improve CO2 tolerance.

Authors :
Fedeli, Paolo
Nigroni, Veronica
Malgrati, Enrico
Cavaliere, Angelo
Cammi, Andrea
Drago, Francesca
Source :
Journal of the American Ceramic Society. Aug2024, Vol. 107 Issue 8, p5668-5681. 14p.
Publication Year :
2024

Abstract

Oxygen transport membranes (OTMs) can be operated as efficient oxygen separators and oxygen distributors, but their diffusion is hampered by the lack of appropriate materials with sufficient chemical stability in operating conditions. Mixed ionic‐electronic conducting SrTiO3‐based perovskite are a promising option due to their remarkable resistance in reducing environments, but they are prone to degradation in CO2‐containing atmospheres owing to carbonate formation. In this study, we propose new Ca1‐xSrxTi0.8Fe0.2O3‐δ perovskites where the Sr2+ cation is partially substituted by Ca2+ to improve the tolerance to CO2. We show that, upon increasing Ca molar fraction, the phase stability in CO2 is progressively improved thanks to the mitigation of carbonate growth. The manufacturing process of the membranes benefits from Ca introduction, which promotes powder densification during sintering. A membrane made of Ca0.1Sr0.9Ti0.8Fe0.2O3‐δ exhibited a stable oxygen flux for 340 h at 900°C when swept with He and for 170 h at 900°C when swept with a gaseous stream containing 40% CO2. Post‐test characterizations confirmed the retention of the crystal structure after the long‐term permeation tests. Ca‐substituted SrTi1‐yFeyO3‐δ perovskites can be considered promising materials for OTMs working in harsh environments and in the presence of CO2. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00027820
Volume :
107
Issue :
8
Database :
Academic Search Index
Journal :
Journal of the American Ceramic Society
Publication Type :
Academic Journal
Accession number :
177677471
Full Text :
https://doi.org/10.1111/jace.19837