Preparation of self-supported dual-phase oxygen permeation membranes via chemical etching method

A novel method called “HCl-chemical etching method” was developed to fabricate self-supported oxygen permeation membranes. Based on this method, Ce0.85Sm0.15O1.925–Ce0.85Sm0.15O1.925/Sm0.6Sr0.4Al0.3Fe0.7O3−δ (SDC–SDC/SSAF) dual-phase self-supported oxygen permeation membranes were successfully prepared. SEM and XRD characterization showed that this dual-phase self-supported membrane is composed of SDC porous support and thin dense SDC/SSAF oxygen permeation layer. In the experiment, the porosity of porous support and thickness of dense layer can be precisely adjusted through this chemical etching technique. Oxygen permeation measurement demonstrated that oxygen permeation flux of SDC–SDC/SSAF dual-phase self-supported membrane reaches 0.43 ml min−1 cm−2 which is much higher than that of untreated samples at the same total membrane thickness. This technique provides a new idea for fabricating self-supported oxygen permeation membrane modules.

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► A HCl-chemical etching method was developed.
► Self-supported SDC–SDC/SSAF dual-phase membranes were fabricated.
► High oxygen flux can be obtained from decreasing membrane thickness.
► Surface modification was essential for dual-phase membranes.