Scalable assembly of functionalized molybdenum disulfide membrane for hydrogen-selective permeation via continuous slot-die coating

Abstract

Two-dimensional (2D) nanosheets can be desirable materials to fabricate membranes for ionic and molecular separation such as water purification, seawater desalination, solvent separation, and gas separation. Molybdenum disulfide (MoS₂) can be a desirable candidate among the family of 2D nanosheets due to their exceptional physical properties, high stability, and well-defined scalable synthesis methods. In this work, a highly aligned MoS₂ layer is fabricated on a centimeter-scale by coating electrochemically exfoliated MoS₂ nanosheets via a continuous slot-die coating method. Particular, an additive to stabilize the resulting dispersion of exfoliated MoS₂ nanosheets further enlarges the capillary width of the stacked MoS₂ nanosheets, which enables the efficient H₂ permeation properties as 5.57 × 10⁻⁶ mol m⁻² s⁻¹ Pa⁻¹ and 13 of H₂/CO₂ ideal selectivity. Furthermore, this MoS₂-based membrane exhibits high thermal stability. While the temperature varies, it shows stable and selective gas permeation properties over 10⁻⁶ mol m⁻² s⁻¹ Pa⁻¹ H₂ permeance, while H₂/CO₂ ideal selectivity remained at 150 °C for 7 days.