Ce0.9Gd0.1O2-δ-based multi-phase membranes with high CO2-tolerance

Abstract

In this work, the oxygen ionic conductor Ce0.9Gd0.1O2-δ was paired with the electronic/mixed conductive oxides, including NiFe2O4 (NFO), La2NiO4+δ (LNO) and Ba0·5Sr0·5Co0·8Fe0·2O3-δ (BSCF), forming three kinds of dual-phase membranes. The performance of the membranes was compared in terms of oxygen flux and CO2 tolerance. The CGO/BSCF provided the highest permeation flux among the three composites with either helium or CO2 fed as the sweep gas, although a sharp decrease of the permeation value was observed for the CGO/BSCF when CO2 was in contact with the membrane. Based on the results for the dual-phase membranes, some CGO/BSCF/NFO triple-phase membranes were developed. The triple-phase membranes were found be less sensitive to the presence of CO2 in the sweep gas than the CGO/BSCF, and the application of the two triple-phase composites instead of the dual-phase ones promoted the oxygen permeation fluxes when the membranes were swept with pure CO2. The results provide valuable information for the material selection and performance optimization of CGO-based multi-phase membranes for oxygen permeation.