Oxygen permeation and stability of Ba0.9Co0.7Fe0.2Nb0.1O3−δ membrane with three-layer structure

• A-site deficiency perovskite as the oxygen permeation membrane.
• A three-layer structure of oxygen permeation membrane.
• Oxygen permeability of membrane significant increased.
• The three-layer structure has a good stability in the 100 h test.

Oxygen permeation membrane with mixed ionic and electronic conductivities is a very attractive technology for the production of oxygen of high purity in an energy- and cost-efficient way. Recently, Ba0.9Co0.7Fe0.2Nb0.1O3−δ perovskite with A-site deficiency has drawn a lot of attentions for its high oxygen permeation flux and good stability. In this work, for further improving the oxygen permeation performance of Ba0.9Co0.7Fe0.2Nb0.1O3−δ membrane, a three-layer structure consisting of a dense thin film and two porous support layers is applied. The three-layer Ba0.9Co0.7Fe0.2Nb0.1O3−δ membrane achieved an oxygen permeation flux as high as 3.93 ml cm−2 min−1 at 900 °C, which is nearly 1.5 times higher than that of the conventional membrane with the same overall thickness. By increasing the flow rate of sweep gas, the oxygen permeation flux of the three-layer membrane was further enhanced up to 4.85 ml cm−2 min−1. A short term stability test of 100 h was conducted and no obvious degradation of the oxygen permeation performance was observed, which indicated that Ba0.9Co0.7Fe0.2Nb0.1O3−δ membrane with a three-layer structure could be very promising for the application in an oxygen generator.

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