Synthesis and Characterization of 40 wt % Ce_0.9Pr_0.1O_{2–<i>δ</i>}–60 wt % Nd_<i>x</i>Sr_1−<i>x</i>Fe_0.9Cu_0.1O_{3−<i>δ</i>} Dual-Phase Membranes for Efficient Oxygen Separation

Abstract

Dense, H2- and CO2-resistant, oxygen-permeable 40 wt % Ce0.9Pr0.1O2–δ–60 wt % NdxSr1−xFe0.9Cu0.1O3−δdual-phase membranes were prepared in a one-pot process. These Nd-containing dual-phase membranes have up to 60% lower material costs than many classically used dual-phase materials. The Ce0.9Pr0.1O2−δ–Nd0.5Sr0.5Fe0.9Cu0.1O3−δ sample demonstrates outstanding activity and a regenerative ability in the presence of different atmospheres, especially in a reducing atmosphere and pure CO2 atmosphere in comparison with all investigated samples. The oxygen permeation fluxes across a Ce0.9Pr0.1O2−δ–Nd0.5Sr0.5Fe0.9Cu0.1O3−δ membrane reached up to 1.02 mL min−1 cm−2 and 0.63 mL min−1 cm−2 under an air/He and air/CO2 gradient at T = 1223 K, respectively. In addition, a Ce0.9Pr0.1O2–δ–Nd0.5Sr0.5Fe0.9Cu0.1O3–δ membrane (0.65 mm thickness) shows excellent long-term self-healing stability for 125 h. The repeated membrane fabrication delivered oxygen permeation fluxes had a deviation of less than 5%. These results indicate that this highly renewable dual-phase membrane is a potential candidate for long lifetime, high temperature gas separation applications and coupled reaction–separation processes.

Keywords

• oxygen separation
• dual-phase membrane
• CO₂ tolerance
• long-term stability
• regenerative ability