Zirconium and Yttrium Co-Doped BaCo_0.8Zr_0.1Y_0.1O_3−δ: A New Mixed-Conducting Perovskite Oxide-Based Membrane for Efficient and Stable Oxygen Permeation

Oxygen permeation membranes (OPMs) are regarded as promising technology for pure oxygen production. Among various materials for OPMs, perovskite oxides with mixed electron and oxygen-ion (e⁻/O²⁻) conducting capability have attracted particular interest because of the high O²⁻ conductivity and structural/compositional flexibility. However, BaCoO_3−δ-based perovskites as one of the most investigated OPMs suffer from low oxygen permeation rate and inferior structural stability in CO₂-containing atmospheres. Herein, zirconium and yttrium co-doped BaCoO_3−δ (BaCo_1−2xZr_xY_xO_3−δ, x = 0, 0.05, 0.1 and 0.15) are designed and developed for efficient and stable OPMs by stabilizing the crystal structure of BaCoO_3−δ. With the increased Zr/Y co-doping content, the crystal structural stability of doped BaCoO_3−δ is much improved although the oxygen permeation flux is slightly reduced. After optimizing the co-doping amount, BaCo_0.8Zr_0.1Y_0.1O_3−δ displays both a high rate and superior durability for oxygen permeation due to the well-balanced grain size, oxygen-ion mobility, crystal structural stability, oxygen vacancy concentration and surface exchange/bulk diffusion capability. Consequently, the BaCo_0.8Zr_0.1Y_0.1O_3−δ membrane delivers a high oxygen permeation rate of 1.3 mL min⁻¹ cm⁻² and relatively stable operation at 800 °C for 100 h. This work presents a promising co-doping strategy to boost the performance of perovskite-based OPMs, which can promote the industrial application of OPM technology.