A GO-Induced Assembly Strategy To Repair MOF Nanosheet-Based Membrane for Efficient H₂/CO₂ Separation

Metal-organic framework (MOF) nanosheets have emerged as promising materials for the construction of molecular sieve membranes due to their nanoscale thickness and highly oriented pore arrays. However, the development of defect-free MOF nanosheet membranes from rigid MOF nanosheets with efficient permselectivity and robust mechanical strength still remains a big challenge. Herein, we develop a facile GO-induced assembly strategy to design continuous and uniform two-dimensional MOF composite membranes, in which the copper 1,4-benzene dicarboxylate (CuBDC) nanosheets present a layer-stacking arrangement. With the assistance of flexible GO, the voids between the junctions of rigid MOF nanosheets are well-repaired, and the interlayer bonding interactions are strengthened, resulting in the fabrication of a continuous nanosheet membrane with robust mechanical strength. The obtained MOF nanosheet-based membranes display remarkable H₂/CO₂ separation performance with a superior H₂ permeance of 9.6 × 10^-7 mol m^-2 s^-1 Pa^-1 and an ideal separation selectivity of 95.1 due to the well-defined size exclusion effect, showing great promise for H₂ separation and purification. The repair strategy described here could also provide the blueprint for the development of other nanosheet-based membranes.