Hollow fiber membranes for hydrogen separation: mechanisms, fabrication, and applications

As a pivotal energy carrier for achieving carbon neutrality and sustainable development, hydrogen (H2) has caused widespread research into high-efficiency separation technologies. Hollow fiber membranes (HFMs) have demonstrated distinct technical superiority in H2 purification and separation, owing to their intrinsic self-supporting architectures, robust mechanical integrity, and exceptional modular scalability. This review first provides an overview of the mass transfer mechanisms of H2 within membranes. Subsequently, it systematically reviews the fabrication technologies for HFMs, including phase inversion, in situ growth, sintering, interfacial polymerization, layer-by-layer assembly, dip coating, and fast current drive synthesis, highlighting the influence of critical preparation parameters on membrane structure and morphology. Building upon these fundamentals, the structural characteristics of different types of HFMs are critically reviewed, followed by a comprehensive analysis of their regulatory rules. Furthermore, as the basis of various application systems, this review provides a detailed discussion of H2-selective and other gas-selective HFMs, with a particular focus on their operational compatibility and performance optimization tailored to specific industrial applications. Finally, future research challenges and perspectives on the industrialization and sustainability of HFMs for H2 separation are proposed.