Engineering robust porous/dense composite hollow fiber membranes for highly efficient hydrogen separation

BaZr_0.7Ce_0.2Y_0.1O_3-δ (BZCY), a perovskite-type mixed protonic and electronic conducting oxide, holds significant potential for H₂ separation and purification as a membrane. The introduction of a porous modification layer as an exchange-active component offers a potential solution to enhance H₂ permeability. However, achieving the desired porous/dense structure presents a notable challenge for practical implementation. In this study, various methods were developed to address sintering kinetics, encompassing both chemical aspects (e.g., interlayer reactions) and physical factors (e.g., thermal expansion), for fabricating a porous BZCY modification layer on a 4-channel BZCY hollow fiber membrane. The optimal composite hollow fiber membrane, resulting from a combination of readily sintered hollow fiber and powders for constructing the porous layers, exhibits an exceptional H₂ permeation flux of 0.48 mL min⁻¹ cm⁻² at 900 °C using 50 % H₂/N₂ as the feed gas, which represents a threefold increase compared to the performance of the bare BZCY membrane. The H₂ permeation flux stabilized at 0.52 mL min⁻¹ cm⁻² for 500 h under water vapor conditions. These findings enabled us to identify the most effective approach, unlocking the full potential of surface-modified hollow fiber membranes and advancing their capabilities in H₂ permeation applications.