Pore Tuning of Metal-Organic Framework Membrane Anchored on Graphene-Oxide Nanoribbon

Although the pore structures and gas transport properties of metal-organic frameworks (MOFs) have been tuned mainly by modifying the framework building blocks, a pore-tuned zeolitic imidazolate framework (ZIF)-8 layer is directly grown on graphene oxide nanoribbons (GONR)-treated polymer substrate. Oxygen-containing functional groups and GONR dangling-carbon bonds facilitated the spontaneous growth of ZIF-8 oriented to the (100) grain on the GONR surface and also enhanced the rigidity by strongly anchoring the ZIF-8 layer by metal-carbon chemisorption. Gas permeation and molecular simulation results confirmed that the effective aperture size of ZIF-8 is adjusted to 3.6 Å. As a result, ultrafast H₂ permeance of 7.6 × 10⁻⁷ mol m⁻² Pa s is achieved while blocking large hydrocarbon molecules. In particular, the membrane showed exceptionally enhanced hydrogen selectivity for the mixture separation than ideal selectivity, owing to the competitive transport between H₂ and large hydrocarbon molecules, and the separation performance surpassed those of ZIF membranes previously fabricated on polymeric supports.