Enhanced CO2-tolerance and hydrogen separation performance of Ba-based ceramic membrane modified by Ce0.9Gd0.1O2-δ surface layer

Abstract

Interest in mixed conducting ceramic membrane for efficient hydrogen separation is growing. However, the membranes with alkaline earth metal are susceptible to CO2 due to the drastic carbonation and irreversible deterioration of membrane, which significantly impedes their applications. Herein, gadolinium-doped ceria (Ce0.9Gd0.1O2-δ, CGO) with robust chemical stability was employed to modify Ba-based dual-phase membrane BaCe0.85Fe0.15O3-δ-BaFe0.85Ce0.15O3-δ (BCF-BFC) by a simple drop coating method. Due to the improved surface activity on the membrane, the CGO-modified BCF-BFC membrane (CGO/BCF-BFC) exhibited an enhanced H2 separation flux of 0.96 mL min−1 cm−2 at 860 °C, which is nearly 1.3-time improvement than the unmodified BCF-BFC membrane. Furthermore, benefitting from the reduction of CO2 adsorption and suppression of carbonate formation on the surface of membrane, an improved CO2-tolerance was observed over the CGO/BCF-BFC, and a high and stable H2 separation flux of 0.60 mL min−1 cm−2 was retained under CO2-containing atmosphere, while BCF-BFC membrane showcased continually deteriorating H2 separation performance at 900 °C. The achieved H2 separation flux along with the improved CO2-tolerance paves a new way towards the future application of alkaline-earth-metal-containing ceramic membrane for H2 purification.