Oriented Titanium‐MOF Membrane for Hydrogen Purification

Abstract Precise hydrogen sorting from purge gas (H2/N2) and coke gas (H2/CH4), commonly carried out by cryogenic distillation, still suffers from low separation efficiency, high energy consumption, and considerable capital cost. Though still in its infancy, membrane technology offers a potential to achieve more efficient hydrogen purification. In this study, an optimum separation of hydrogen towards both methane and nitrogen via a kinetically‐driven mechanism is realized through preferred orientation control of a MOF membrane. Relying on the 0.3 nm‐sized window aligned vertical to the substrate, b‐oriented Ti‐MOF membrane exhibits ultra‐high hydrogen selectivity, surpassing the upper bound limit of separating H2/N2 and H2/CH4 gas pairs attained so far by inorganic membranes. This spectacular selectivity is combined with a high H2 permeability owing to the synergistic effect of the 1 nm‐sized MOF channel.