Influence of Ln elements (Ln = La, Pr, Nd, Sm) on the structure and oxygen permeability of Ca-containing dual-phase membranes

• Published in: Separation and purification technology Vol. 251; p. 117361
• Main Authors: Wang, Shu, Shi, Lei, Boubeche, Mebrouka, Wang, Xiaopeng, Zeng, Lingyong, Wang, Haoqi, Xie, Zhiang, Tan, Wen, Luo, Huixia
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2020
• Subjects: CO2 stability; Composite oxide; Oxygen permeable membrane; Oxygen separation; Pechini one-pot method; Oxygen permeable membrane; Pechini one-pot method; CO2 stability; Oxygen separation; Composite oxide
• ISSN: 1383-5866
• DOI: 10.1016/j.seppur.2020.117361

[Display omitted] •New 60wt.%Ce0.9Ln0.1O2-δ-40wt.%Ln0.6Ca0.4FeO3-δ dual-phase membranes are reported.•These new Ca-containing membranes show comparable CO2-tability and phase stability.•Co-Free CLnO-LnCFO membranes are economic and ecological.•CPO-PCFO shows highest oxygen permeability and stability among these compounds. Developing good performance and low-cost oxygen permeable membranes for CO2 capture based on the oxy-fuel concept is greatly desirable but challenging. Despite tremendous efforts in exploring new CO2-stable dual-phase membranes, its presence is however still far from meeting the industrial requirements. Here we report a series of new Ca-containing CO2-resistant oxygen transporting membranes with composition 60wt.%Ce0.9Ln0.1O2-δ-40wt.%Ln0.6Ca0.4FeO3-δ (CLnO-LnCFO; Ln = La, Pr, Nd, Sm) synthesized via a Pechini one-pot method. Our results indicate all investigated compounds are composed of perovskite and fluorite phases, while the perovskite phases in the CNO-NCFO and CSO-SCFO membranes after sintering generates Ca-rich and Ca-less two kinds of grains with different morphologies, where the Ca-less small perovskite grains block the transport of oxygen ions and eventually result in poor oxygen permeability. Among our investigated CLnO-LnCFO membranes, CPO-PCFO exhibits the highest oxygen permeability and excellent CO2 stability, which were mainly associated with the improvement in crystal symmetry, non-negligible electronic conductivity of fluorite phase and the enhancement in electronic conductivity of perovskite. Our results establish Ca-containing oxides as candidate material platforms for membrane engineering devices that combine CO2 capture and oxygen separation.