Influences of Al substitution on the oxygen permeability through 60 wt%Ce0.9La0.1O2-δ-40 wt%La0.6Sr0.4Co1-xAlxO3-δ composite membranes

• Published in: Separation and purification technology 2021-11, Vol.274, Article 119042
• Main Authors: Li, Dongcheng, Wang, Xiaopeng, Tan, Wen, Huang, Yanhao, Zeng, Lingyong, He, Yiyi, Yu, Peifeng, Luo, Huixia
• Format: Article
• Language: English
• Subjects: Al doping; CO2 stability; Dual-phase membrane; Gas separation; Oxygen permeation
• ISSN: 1383-5866; 1873-3794
• DOI: 10.1016/j.seppur.2021.119042

[Display omitted] •New 60 wt%Ce0.9La0.1O2-δ-40 wt%La0.6S0.4Co1-xAlxO3-δ composite membranes are reported.•CLO-LSCAO membranes show high oxygen permeability.•CLO-LSCAO membranes show excellent stability under CO2 atmosphere.•Substitution for Co by Al is economic and ecological. There is a common trade-off between the oxygen permeability and stability of the oxygen permeable membranes, which significantly hinders their practical applications in modern clean energy industries like oxyfuel power plants and process intensifications like the reaction together with separation in one apparatus. Herein we reported a series of previously unreleased ceramic composite oxygen transport membranes 60 wt%Ce0.9La0.1O2-δ-40 wt%La0.6Sr0.4Co1-xAlxO3-δ (denoted as 60CLO-40LSC1-xAxO) with excellent CO2 stability and acceptable oxygen permeability, where x = 0.05, 0.1, 0.2, 0.3, 0.35. Study results demonstrated that all compositions (60CLO-40LSC1-xAxO; x  = 0.1, 0.2, 0.3, 0.35) clearly consisted of two phases at all doping concentrations (x = 0.05, 0.1, 0.2, 0.3, 0.35) after sintering at 1250 ℃ for 5 h except for x = 0.05. The oxygen permeation flux initially increases with the increment of aluminum doping content in the range of 0–0.1 and reaches the highest oxygen permeation flux for x = 0.1, followed by the decrease of oxygen permeation flux as x enhances. The optimal doping composition shows a comparable oxygen permeation rate of 1.02 mL cm−2 min−1 at 1000 ℃ under air/He gradient and works steadily under a pure CO2 environment for 50 h, providing potential applications in oxy-fuel combustion.