Highly stable dual-phase Y0.8Ca0.2Cr0.8Co0.2O3–Sm0.2Ce0.8O1.9 ceramic composite membrane for oxygen separation

• Dense highly stable dual-phase ceramic membranes were fabricated at 1400 °C.
• Ca- and Co-doped yttrium chromite provided excellent electronic conductivity.
• Samaria-doped ceria provided high ionic conductivity and phase stability.
• O2 permeation characteristics are adequate for O2 separation.

A highly stable ceramic composite membrane composed of Ca- and Co-doped yttrium chromite, Y0.8Ca0.2Cr0.8Co0.2O3 (YCCC), and samaria-doped ceria, Sm0.2Ce0.8O1.9 (SDC), was demonstrated for oxygen separation. Homogeneously dispersed nano-scale composite powders were synthesized by a single-step combustion process based on the glycine–nitrate method. Dense composite membranes were achieved having submicron grain sizes and well-percolated electronic and ionic conduction pathways. Densification of the composite membrane was assisted by liquid phase sintering caused by cobalt-doping in yttrium chromite, and gas-tight membranes are fabricated at 1400 °C. The YCCC and SDC phases were chemically and thermo-mechanically compatible at both processing and operating temperatures. The composite membrane exhibited an oxygen permeation flux comparable to those of the state-of-the-art single-phase membrane materials and excellent stability in harsh operating conditions under a H2–CO2 environment for long-term operation, which suggests potential application in various combustion and fuel production processes.

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