MOF-induced hetero-nucleation engineering enables HOF-based composite membranes for high-permeance hydrogen purification

Herein, we have designed the all-nanoporous composite (ANC) membranes with metal-organic framework (MOF) fillers and hydrogen-bonded organic framework (HOF) matrix, achieving high-permeance H₂ purification. The hetero-MOF facilitates the heterogeneous nucleation, offsetting the need for a highly supersaturated solution to achieve sufficient nucleation density during solution processing. Continuous MOF/HOF ANC membranes are realized by suppressing the homogeneous nucleation, equilibrating the nucleation driving force with the molecular attachment rate, and balancing the nutrient supply and demand. The optimized <em>ns</em>-CuBDC/HOF-30-100 ANC membrane shows synchronously improved H₂ permeance and H₂/CH₄ selectivity by 562% and 241% compared to the pristine HOF membrane. The <em>ns</em>-CuBDC/HOF-30-100 ANC membrane inherits the pressure-responsive behavior from the parent HOF, exhibiting further improved H₂ permeance up to 9842 GPU and slightly changed H₂/CH₄ selectivity of 30.01 at 2.0 bar. The MOF/HOF ANC membrane manifests that incorporating a porous hetero-phase effectively upgrades the gas separation performance, and the HOF matrix circumvents the performance constraints of the traditional polymer matrix while preserving the solution-processability.