Ultrathin Nonswelling NbTe ₂ Nanosheet Membranes for Fast and Tight Molecular Sieving

Two-dimensional (2D) membrane separation technology has attracted enormous attention to address freshwater scarcity due to tunable nanochannels for mass transport and high molecular sieving efficiency. However, many 2D lamellar membranes face challenges for long-term stability due to swelling in polar solvents. To overcome these limitations, we report niobium ditelluride (NbTe2) as a transition metal telluride (TMT) membrane material for efficient molecular separation. The NbTe2 nanosheet colloid solution was prepared through solid lithiation and exfoliation, and then fabricated into NbTe2 membranes via vacuum filtration. The NbTe2 membrane stands out for its low functional group density, which imparts excellent antiswelling properties in various solvent environments, thus ensuring membrane stability without extensive modifications. The NbTe2 membrane demonstrate 99% dye retention for methyl blue (MB), Coomassie brilliant blue (CBB), Congo red (CR), and Eriochrome black-T (EB-T) dye with high water permeance (up to 180 L·m–2·h–1·bar–1) due to the subnanometer nanochannels and super hydrophilic surface of membrane. This study demonstrates the unique capabilities of NbTe2 membranes, suggesting their potential as a robust solution for molecular sieving applications and expanding the possibilities for 2D membrane development.