Bottom-Up Synthesis for Defect-Free Two-Dimensional MoS₂ Sieving Membranes

Membranes have seen growing interest in employing 2D materials for water treatment and desalination, aiming to enhance the performance of the current technologies. Among these 2D materials, MoS2 nanosheets have recently attracted significant attention. Current fabrication approaches of MoS2-based membranes require intensive electrochemical or sonication steps, which may hinder scalability. Besides, top-down methods usually produce MoS2 slabs with large size distributions, creating detrimental defects affecting selectivity. We present a single-step bottom-up MoS2 synthesis that yields highly concentrated solutions containing exclusively MoS2 single-layer nanosheets allowing a perfect laminar stacking on poly(ether sulfone) (PES) support leading to excellent monovalent salt rejection (99.7% ± 0.5 NaCl).