Novel dual-phase ceramic membrane for sustainable oxygen separation

Abstract

Mixed ionic–electronic conducting (MIEC) perovskite oxide membranes are greatly required in fields of oxygen separation. In this study, Gadolinium-doped Cerium (GDC) and La₂NiO₄ (LNO) powders are prepared into dual-phase perovskite membranes by ball-milling and sintering. The mixed membranes show a distorted perovskite phase with orthorhombic structure and cubic structure. For oxygen permeability of membranes, the fluxes increase with the enhancement of temperatures or He sweep gas flows. The effects of four doping ratios (10 %, 20 %, 30 %, and 40 %) on oxygen permeability are discussed. Compared with the LNO membrane, the oxygen permeation fluxes of the four mixed membranes show varying degrees of improvement. And, the optimal doping ratio is 20 wt.%. The maximum oxygen permeation flux is ∼3.53 mL·min⁻¹·cm⁻² in all test conditions. To further investigate the influence of different conditions on oxygen permeability, Arrhenius activation energy theory, kinetic analysis, and improvement factor are introduced to support the hypothesis. Simultaneously, the membranes have excellent tolerance to CO₂ atmosphere. The long-time stability (∼1200 min) under CO₂ atmosphere and recovery capability can endow the dual-phase perovskite membrane with great potential for numerous applications.