Hydrogen permeation through dual-phase ceramic membrane derived from automatic phase-separation of SrCe0.50Fe0.50O3-δ precursor

Abstract

Dense ceramic membranes with mixed protonic-electronic conductivity have been widely studied because of their 100% H2 selectivity and directly integrated advantage with high-temperature chemical reactions. In this study, Sr-based dual-phase ceramic membrane SrCe0.95Fe0.05O3-δ-SrFe0.95Ce0.05O3-δ (SCF-SFC) with mixed protonic-electronic conductivity was obtained by automatic phase-separation of SrCe0.5Fe0.5O3-δ (SCF55) precursor. After calcination at 1350 °C, the rationally designed SCF55 precursor auto-decomposed into two thermodynamically stable oxides: Ce-rich phase SrCe0.95Fe0.05O3-δ and Fe-rich phase SrFe0.95Ce0.05O3-δ that functioned as protonic and electronic conductors, respectively. The compositions and microstructures of the auto-formed phases were studied via XRD and SEM analyses. The dual-phase SCF-SFC membrane shows a high hydrogen permeation flux of 0.38 mL min−1 cm−2 at 940 °C. Stability tests indicated that the SCF-SFC membrane exhibited higher and more stable hydrogen permeation flux with less degradation under CO2-containing atmospheres compared with the BaCe0.15Fe0.85O3-δ-BaCe0.85Fe0.15O3-δ (BCF-BFC) membrane. This significant improvement can be attributed to the lower CO2 adsorption and reduced carbonate formation which is indicated by thermogravimetric analysis.