Ceramic-carbonate dual-phase membrane for ICCU-DRM

Membrane based materials have also been developed for ICCU-DRM. The details methods are indicated below, copied from this reference (https://doi.org/10.1016/j.cej.2019.122182):

“Preparation of the powder materials

The Ce_0.8Sm_0.2O_2-δ (SDC) powder was prepared through a co-precipitation method according to the previous work [61], briefly description as follows. Main chemicals were chosen as follows: cerium nitrate hexahydrate and samarium (III) nitrate hexahydrate (supplied by Sigma-Aldrich). The samarium (III) nitrate hexahydrate solution was combined with the cerium nitrate hexahydrate solution according to the computational molar ratios, e.g. 20 mol% samarium in ceria. An appropriate amount of oxalate acid solution (1 M) was added into the above mixed solution to prepare the SDC precursor. The precipitate was washed three times in deionized water, followed by ethanol washing for three times in order to remove water from the particle surfaces. The obtained precipitates were dried in an oven at 100 °C overnight. The precursor powder was finally sintered at 700 °C for 2 h to obtain the final SDC powder. LaNiO₃ (hereinafter referred to as LNO) and La_0.9Ce_0.1NiO_3-δ (hereinafter referred to as LCNO) powders were prepared through a sol–gel method [62]. As an example, the synthesis process of LNO can be briefly stated as follows. Stoichiometric amounts of the corresponding metal nitrates, i.e., La(NO₃)₃·5H₂O, and Ni(NO₃)₂·6H₂O were fully dissolved and mixed in deionized water to form an aqueous solution. And then, citric acid and ethylene glycol with the mole ratio of citric acid: ethylene glycol: metal ions = 1.5:1.5:1 were added to the above solution. The solution was vigorously stirred and evaporated in a water bath (80 °C) to get viscous gel. The obtained precursor-gel was then dried and followed by calcination at 800 °C for 6 h. The LCNO powder was prepared by the same preparation method of the LNO. Both LNO and LCNO powders were reduced in pure H₂ at 750 °C for 1 h to be used as catalysts before being packed in the membrane reactor. The mixed phase of LNO/SDC was prepared by ball milling method with the ratio of LNO:SDC = 15 wt%:85 wt%.”

“Preparation of the membranes

The preparation method of the LNO/SDC-carbonate membrane was similar to our previous work [53]. Appropriately the mixed LNO/SDC powder was placed into 14 mm stainless steel die and pressed under 200 MPa to achieve a gray disk. The disk was then sintered at 1150 °C in the air for 6 h (with a heating rate of 3 °C·min⁻¹) to form support of the membrane. One side of the support disk was brought in contact with a carbonate melt composed of Li₂CO₃ and Na₂CO₃ with a molar ratio of 52:48 mol%, pre-heated to 600 °C. The infiltration time was 1 h, sufficient to allow the molten carbonate to fill the pore canal of the LNO/SDC support. After cooling, the excess carbonate on the surface of the membrane was removed by slightly polishing with sandpaper. The thickness of the final membrane was about 0.6 mm.”