Molecular-scale hybrid membranes containing benzimidazole linkages on large-area α-alumina tubes for H2 purification

H2/CO2 separation is important in industry. Polymer, inorganic and hybrid membranes have been reported, however, high performance membranes with good scalability and large area are still lacked. Here, we fabricated a series of molecular-scale hybrid membranes (MHMs) containing benzimidazole linkages on rough α-alumina tubes. The membranes, with an area of 37.7 cm2 for each, exhibited a H2/CO2 selectivity of 14.2 (with a corresponding H2 permeance of 29.5 GPU) at 423 K and high H2 permeance of 310 GPU (with a corresponding H2/CO2 selectivity of 9.37) at 523 K. The membranes had good pressure and temperature tolerance. Besides, a two-stage membrane system was designed to study the effect of pressure and membrane area on hydrogen production. [Display omitted] •Molecular-scale hybrid membranes were fabricated on large-area rough α-alumina tubes.•Facile interfacial polymerization protocol was used.•The membranes exhibited good performance for H2/CO2 separation.•The membranes possessed high temperature and pressure resistance.•A two-stage membrane process was designed.