Rational design via tailoring Mo content in La2Ni1-xMoxO4+δ to improve oxygen permeation properties in CO2 atmosphere

• Published in: Journal of alloys and compounds Vol. 806; pp. 153 - 162
• Main Authors: Han, Ning, Wei, Qing, Zhang, Shuguang, Yang, Naitao, Liu, Shaomin
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 25.10.2019; Elsevier BV
• Subjects: Bulk density; Carbon dioxide; CO2 resistance; Diffusion layers; Doping; Fluxes; Membrane; Membranes; Oxygen ions; Oxygen permeation; Oxygen transfer; Penetration; Permeability; Perovskites; Ruddlesden-popper oxide; Stability; Membrane; CO2 resistance; Ruddlesden-popper oxide; Doping; Oxygen permeation
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2019.07.209

Perovskite (ABO3) and ruddlesden-popper (A2BO4) oxides are typical mixed conducting ceramic membrane materials for oxygen separation from air. In particular, ruddlesden-popper (RP) membrane display high CO2 resistance despite their relative low oxygen permeation flux compared to perovskite oxide membranes. Element-doping is an important method to improve the oxygen permeability. In this work, the mechanism of oxygen transfer process through one RP ceramic La2Ni1-xMoxO4+δ (x = 0, 0.025, 0.05, 0.1, 0.2) membranes was investigated. An optimum doping level (x = 0.05) in La2Ni1-xMoxO4+δ was found. The optimized composition of La2Ni0.95Mo0.05O4+δ membrane could not only improve surface oxygen exchange reactions, but also promote oxygen ion bulk diffusion through the dense layer. The maximum oxygen flux of La2Ni0.95Mo0.05O4+δ membrane reached 3.27 mL min−1 cm−2 at 1000 °C. Furthermore, La2Ni0.95Mo0.05O4+δ membrane high stability in CO2 atmosphere. When sweeping gas was switched from helium to pure CO2, the oxygen fluxes were only reduced by 5% and stabilized at 2.75 mL min−1 cm−2 at 950 °C. Our results highlight the efficiency of Mo-doping strategy to simultaneously improve the oxygen permeability and stability of A2BO4+δ-type oxide membranes. •The influences of the Mo dosage inside La2NiO4+δ system on the oxygen permeability are investigated.•La2Ni0.95Mo0.05O4+δ with orthorhombic structure displays the best oxygen permeability.•La2Ni0.95Mo0.05O4+δ displays great CO2-resistance with oxygen permeation flux of 2.75 mLmin−1cm−2 at 950 °C swpet by CO2.