Shu Wang,Xiaopeng Wang,Yanhang Huang,Lingyong Zeng,Yiyi He,Mebrouka Boubeche,Huixia Luo
Previously unreported Ce 0.9 Pr 0.1 O 2- δ -Pr 0.6 Ca 0.4 MnO 3- δ (CPO-PCMO) dual-phase membrane is designed and successfully fabricated. The crystal structure, surface morphology, stability, and oxygen permeability is systematically investigated. The XRD results reveal that CPO-PCMO dual-phase membranes are made up of cubic fluorite phase and orthorhombic perovskite phase, which exhibit excellent stability at elevated temperature under air atmospheres as well as various low oxygen conditions such as Ar or CO 2 atmospheres. In addition, no obvious holes, cracks, and impurities are observed. The obtained CPO-PCMO membrane with 0.8 mm thickness exhibits comparable oxygen permeability with a flux of 0.23 mL min −1 cm −2 under air/He gradient at 1000 °C and stably works over 300 min without obvious deterioration under air/CO 2 gradient, suggesting it has good CO 2 stability.
Libin Zhuang,Jiaqi Li,Jian Xue,Zhouyang Jiang,Haihui Wang
Adding metal phase as the electronic transport channels in mixed protonic and electronic conductors is an effective method to enhance the conductivity and hydrogen permeability. Ceramic-metal (cermet) Ni-BaCe 0.85 Fe 0.15 O 3-δ (Ni-BCF8515) dual-phase membranes were successfully fabricated in this article, where BaCe 0.85 Fe 0.15 O 3-δ (BCF8515) served as the protonic conductor and Ni acted as the electronic conductor. The hydrogen permeability of Ni-BCF8515 dual-phase membrane was improved apparently, reaching 0.325 mL min −1 cm −2 at 1000 °C, which is four times higher than that of the single phase BCF8515 membrane. Hydrogen permeability of Ni-BCF8515 dual-phase membrane under different hydration conditions was studied here. Moreover, Ni-BCF8515 dual-phase membrane showed stable hydrogen permeability under the reducing atmosphere for 50 h.
Peng Zhang,Song Wang,Bingjie Pang,Xuefeng Zhu,Weishen Yang
High temperature dual-phase mixed conductor membranes are promising for CO 2 separation and utilization. Most efforts are focused on materials, thickness, microstructural features and surface modifications of the electronic conducting phase. Here, we unveil the effect of the carbonate-ionic conducting phase on CO 2 permeation process with a dense NiO-based dual-phase membrane. The results demonstrate that the CO 2 flux increases first and then decreases with the increase of Li 2 CO 3 addition amount. The controlling step of CO 2 permeation changes from bulk diffusion to surface reaction as much more Li 2 CO 3 was added into the carbonate-ionic conducting phase. Model analysis indicates that the peroxide formation process on the membrane surface is the rate-limiting step, which is closely related to the oxygen solubility of molten carbonate.
A new series of layered perovskite K 2 NiF 4 structure La 2 Ni 1-x Sb x O 4+δ (LNSx, x = 0, 0.025, 0.05) were used to prepare the LNSx-molten carbonate (MC) dual-phase membrane for CO 2 separation. Sb doping at the Ni site is expected to enhance CO 2 permeability and improve the resistance towards CO 2 /carbonate corrosion. In this work, the CO 2 permeability of the LNSx- MC membrane was investigated for CO 2 -containing atmospheres with and without oxygen, and correlated with the lattice characteristics, microstructure, chemical bond, and conductivity of LNSx support. The result shows that the introduction of Sb improves the structure symmetry and increases the interstitial oxygen concentration, which is beneficial for oxygen ion transport. The superior CO 2 permeability of Sb-doped sample is confirmed by the higher permeation fluxes with value of 0.15 mL min −1 cm −2 at 800 °C of LNS0.025-MC dual-phase membrane in 50% CO 2 + 50% N 2 . In addition, the LNS0.025-MC dual-phase membrane achieves a great enhancement in chemical and structural stability compared to the LNS0. In the simulated flue gas 15% CO 2 + 10% O 2 + 75% N 2 , the LNS0.05-based dual phase membrane shows a high permeation flux of 1.07 mL min −1 cm −2 at 800 °C, which is 2 times higher than that of LNS0-based dual-phase membrane.
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