A layered perovskite La2Ni1-xSbxO4+δ-molten carbonate dual-phase membrane for CO2 separation

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.