Synthesis and characterization of perovskite materials for production of mixed ionic and electronic conduction membranes

Abstract

The need of a clean energy delivery is increasing daily with the changes taking place around the planet. Oxygen separation methods for coal power plants are a good option to reach the demands and goals, since some idealized systems show great potential for controlling carbonic gas emissions. Recent studies with dense membranes are optimistic about the application of this technology in the oxygen separation process. Perovskites have been used as a strategic material to produce dense membranes, since it has the ability to transport ions and electrons simultaneously. Best results reported so far are for the Ba0.5Sr0.5Co0.8Fe0.2O3- (BSCF) perovskite. In this work, the BSCF perovskites were synthesized by two variations of the sol-gel method in order to reach the optimum properties for the preparation of dense membranes. A correlation between the material properties and synthesis parameters were studied and a route was suggested for future studies. Also, partial substitution of cesium, yttrium and scandium on the perovskite structure was performed in order to assess the ability of the structure to accommodate foreign cations and change the properties of the final material. Partial substitution with cesium on the A-site was not possible, however yttrium and scandium were successfully incorporated. Oxygen vacancy concentration allowed estimation of improvements on the oxygen permeation of the membranes. Moreover, the stability of the perovskite with scandium was measured under CO2 atmosphere, confirming promising improvements on the membranes stability.