Oxygen permeation flux through 10Sc1YSZ-MnCo2O4 asymmetric membranes prepared by two-step sintering
Asymmetric membranes based on a dual phase composite consisting of (Y2O3)(0.01)(Sc2O3)(0.10)(ZrO2)(0.89) (10Sc1YSZ) as ionic conductor and MnCo2O4 as electronic conductor were prepared and characterized with respect to sinterability, microstructure and oxygen transport properties. The composite membranes were prepared by tape casting, lamination and fired in a two-step sintering process. Microstructural analysis showed that a gastight thin membrane layer with the desired ratio of ionic/electronic conducting phases could be fabricated. Oxygen permeation fluxes across the 10SclYSZ/MnCo2O4(70/30 vol%) composite membrane were measured from 750 to 940 degrees C using air or pure oxygen as feed gases and N-2 or CO2 as sweep gases. Fluxes up to 2.3 ml(N) min(-1-) cm(-2) were obtained for the 7 pm thick membrane. A degradation test over 1730 h showed an initial degradation of 21% during the first 1100 h after which stable performance was achieved. The observed degradation is attributed to coarsening of the infiltrated catalyst.