Brownmillerite (BM)-type oxide sorbents have gained attention recently for producing oxygen-enriched streams. Herein, a cost-effective method of quenching with the use of an Al foil pad is adapted for the synthesis of brownmillerite SrCoO 2.5 . The oxygen storage capacity of this oxide has been investigated using a simple home-built volumetric setup. The oxygen-rich phase was formed by a pressurized heat-treatment of a BM sample. The oxygen storage capacity of the sample has been calculated from the pressure change during desorption. The effect of oxygen pressure on the amount of oxygen stored inside the sample has also been evaluated. Furthermore, selective absorption of oxygen is confirmed by performing the absorption in compressed air. The results indicate that 15.28 cm 3 O 2 g −1 can be stored in the sample at STP. The change in oxygen content in SrCoO 2.5+δ varied reversibly up to a δ value of 0.26, which is confirmed by iodometric titration. It is shown that the new method of quenching proposed does not deteriorate the oxygen storage property of the material.

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Oxygen storage materials with low operating temperatures have gained attraction in oxygen separation and enrichment applications. Herein, YBaCo 2 O 6−x , Dy 0.5 Y 0.5 BaCo 2 O 6−x and DyBaCo 2 O 6−x are explored for low-temperature oxygen enrichment. These oxides were synthesized through solid-state reaction and the oxygen separation properties at various temperatures were studied using a home-built volumetric setup. The oxygen intake temperatures of the sample were found to vary depending upon the rare-earth cation size. The lowest absorption temperature of 523 K was observed for DyBaCo 2 O 6−x. Interestingly, DyBaCo 2 O 6−x had the largest saddle point radii through which oxide ion migration occurs. The effect of the synthesis method and microstructure on the oxygen holding capacity of DyBaCo 2 O 6−x has also been analyzed. For this, DyBaCo 2 O 6−x was synthesized through a combination of solution combustion synthesis followed by calcination and sintering at different temperatures. The particle size was found to have a profound effect on the oxygen intake of DyBaCo 2 O 6−x .

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