Structure Regulation of MOF Nanosheet Membrane for Accurate H2/CO2 Separation

High-purity H₂ production accompanied with a precise decarbonization opens an avenue to approach a carbon-neutral society. Metal-organic framework nanosheet membranes provide great opportunities for an accurate and fast H₂ /CO₂ separation, CO₂ leakage through the membrane interlayer galleries decided the ultimate separation accuracy. Here we introduce low dose amino side groups into the Zn₂ (benzimidazolate)₄ conformation. Physisorbed CO₂ served as interlayer linkers, gently regulated and stabilized the interlayer spacing. These evoked a synergistic effect of CO₂ adsorption-assisted molecular sieving and steric hinderance, whilst exquisitely preserving apertures for high-speed H₂ transport. The optimized amino membranes set a new record for ultrathin nanosheet membranes in H₂ /CO₂ separation (mixture separation factor: 1158, H₂ permeance: 1417 gas permeation unit). This strategy provides an effective way to customize ultrathin nanosheet membranes with desirable molecular sieving ability.