Two-Dimensional Transition-Metal Dichalcogenide-Based Membrane for Ultrafast Solvent Permeation

Transition-metal dichalcogenides (TMDs) represent an emerging class of materials showing promise in a variety of applications. The judicious stacking of two-dimensional (2D) TMDs has been reported to give high-flux and energy-efficient membranes for high-resolution molecular sieving, with permeation greater than the state-of-the-art graphene-based membranes of comparable thickness. Unfortunately, current TMD-based membranes can only be used for aqueous solutions but not organic solvents, which limits their scope of application. Furthermore, it remains a challenge not only to reduce the spacing of interlayers sufficiently to exclude small molecules but also to maintain the high resolution in the face of the expected swelling when immersed in organic solvents for prolonged periods. Herein, we demonstrate the precise control of the interlayer spacing of anionic TMD laminates using cationic layered double hydroxide (LDH) nanosheets. Moreover, the controlled interlayer distance of the TMD/LDH lamellar (TLL) membrane exhibited almost 100% rejection of organic dyes, with molecular weight as small as 327 g mol^–1, dissolved in acetone, while maintaining excellent long-term stability at an ultrafast permeance that is 2–3 orders-of-magnitude higher than that of the reported ones with similar rejection. Our study opens up new perspectives for the use of 2D TLL membranes in a variety of critical separation technologies.