Highly Stable Dual-Phase Membrane Based on Ce0.9Gd0.1O2-La2NiO4+ for Oxygen Permeation under Pure CO2 Atmosphere

Dense oxygen ion-conducting ceramic membranes with CO2 resistance can promote many advanced applications such as membrane reactors for green chemical synthesis and oxy-fuel combustion for clean energy delivery. The state-of-the-art perovskite oxide membranes are characterized by their high O-2 flux but low stability in a CO2-containing atmosphere. To solve this problem, dual-phase membranes have captured the imagination of researchers. Herein, a novel dual-phase hollow fiber membrane with a composition of 40wt% Ce0.9Gd0.1O2- (GDC)-60wt% La2NiO4+ (LNO) is developed via a combined phase inversion sintering process. During the high temperature treatment, La-doping behavior is observed with La leaching out from the LNO phase and diffusing into the GDC phase. This dual phase membrane displays the O-2 flux of 1.47 at 950 degrees C, which is reduced by 10% to 1.31mLmin(-1)cm(-2) when the sweep gas is switched from helium to pure CO2. Such minor O-2 flux reduction is due to the strong CO2 adsorption on membrane surface occupying the O-2 vacancies without permanent membrane damage, which is fully eliminated by an inert gas purge. Such a robust dual-phase membrane exhibits the potential to overcome the low stability problem under the CO2-containing atmosphere.