The effect of Strontium contents on novel MIEC1-MIEC2 dual-phase ceramic-based oxygen transport membranes

Abstract

Although ceramic-based oxygen transport membranes (OTMs) have irreplaceable advantages over traditional oxygen production technologies, their oxygen permeability and stability need to be further improved. Based on the theoretical starting point of increasing the three-boundary reaction zone and reducing blocking effect, a set of new dual-phase membranes 75wt%Ce0.8Sm0.1Cu0.1O2-δ-25wt%-Sm0.8Sr0.2Co0.8Fe0.2O3-δ (CSC-8282) and 75wt%Ce0.8Sm0.1Cu0.1O2-δ-25wt%Sm0.3Sr0.7Co0.8Fe0.2O3-δ (CSC-3782) with different strontium contents were prepared by a one-pot sol-gel method ensuring that each element has the same chemical potential. The surface morphology, crystal structure and element distribution are systematically studied by SEM, XRD and EDS, which confirms that the synthesized membranes have an obvious dual-phase structure and excellent compactness. The results of the oxygen permeability experiment show that the oxygen permeability of CSC-3782 is always higher than that of CSC-8282 under any conditions due to the inducing effect of strontium on oxygen vacancies, and flow rate of CSC-3782 at 960°C reached 0.64 and 0.22mL⋅cm-2⋅min-1 for He and CO2 as a sweep gas, respectively. The final long-term stability test confirmed that the dual-phase composite membrane with great prospects for development has high temperature stability and CO2-tolerant property, and the doping of strontium to A-site of perovskite contributes to the improvement of its performance.