Structural and functional properties of SrTi1-xFexO3-δ (0 ≤ x ≤ 1) for the use as oxygen transport membrane

F. Schulze-Küppers, S. F.P. Ten Donkelaar, S. Baumann*, P. Prigorodov, Y. J. Sohn, H. J.M. Bouwmeester, W. A. Meulenberg, O. Guillon

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

30 Citations (Scopus)

Abstract

Perovskitic oxides are widely investigated as oxygen transport membrane materials for the efficient generation of pure oxygen or the use in membrane reactors. However, most of high performance perovskites suffer from low stability in operation conditions. Therefore, solid solutions of SrTi1-xFexO3-δ (STF) are investigated due to the initial high stability of the strontium titanate host lattice. Self-synthesized powders with substitution of Ti by 0%, 25%, 35%, 50%, 75%, and 100% Fe were studied. Crystal structure, functional properties i.e., diffusion coefficient, surface exchange rates, and oxygen permeation rates as well as membrane fabrication and operation related material properties i.e. sintering behaviour and thermal/chemical expansion were investigated. Substitution of Ti by Fe increases oxygen mobility and, hence, oxygen permeation rates, but reduces stability in operation relevant atmospheres such as Ar/4%H2 or CO2. At the same time thermal/chemical expansion increases. This makes the fabrication of supported thin membranes and their integration into membrane modules more challenging. It turned out that 25-35% Fe substituting Ti seems to be a good compromise between structural and functional properties. Oxygen permeation rates achieved are comparable to that of standard materials such as La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF). At the same time stability is higher and thermal expansion coefficients lower compared to LSCF, which makes STF with limited Fe-content (max. 35%) a promising oxygen transport membrane material.

Original languageEnglish
Pages (from-to)414-421
Number of pages8
JournalSeparation and purification technology
Volume147
DOIs
Publication statusPublished - 16 Jun 2015

Keywords

  • Microstructure
  • Oxygen permeation
  • Oxygen transport membrane
  • STF
  • Thermal expansion

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