Structure Regulation of MOF Nanosheet Membrane for Accurate H /CO Separation.

High-purity H 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 H /CO separation, CO leakage through the membrane interlayer galleries decided the ultimate separation accuracy. Here we introduce low dose amino side groups into the Zn (benzimidazolate) conformation. Physisorbed CO served as interlayer linkers, gently regulated and stabilized the interlayer spacing. These evoked a synergistic effect of CO adsorption-assisted molecular sieving and steric hinderance, whilst exquisitely preserving apertures for high-speed H transport. The optimized amino membranes set a new record for ultrathin nanosheet membranes in H /CO separation (mixture separation factor: 1158, H permeance: 1417 gas permeation unit). This strategy provides an effective way to customize ultrathin nanosheet membranes with desirable molecular sieving ability.