Atomistic insights into water and ion transport in GO-MoS2 hybrid membranes.

Hybrid membranes composed of graphene oxide (GO) and molybdenum disulfide (MoS2) offer promising opportunities for overcoming the permeability-selectivity trade-off in membrane-based desalination. However, the influence of layer composition and stacking sequence on water and ion transport remains insufficiently understood at the molecular level. In this work, non-equilibrium molecular dynamics simulations were employed to systematically investigate pressure-driven water and ion transport through six GO-MoS2 membrane architectures, including pristine GO and MoS2 membranes and four hybrid stacking configurations. The results demonstrate that membrane architecture strongly governs the balance between water transport and ion exclusion. Pristine MoS2 exhibits the highest water transport rate, whereas GO-containing configurations generally show lower ion accessibility to the confined membrane region. Molecular-level analyses reveal that water transport is governed by the coupled effects of channel confinement, interfacial interactions, molecular packing, hydrogen bonding, and surface chemistry. Hydration-shell analysis further shows distinct responses of Na+ and Cl- under confinement, contributing to their different penetration behavior. The results highlight that the stacking sequence and surface composition of GO-MoS2 membranes provide an effective means of tuning water transport and ion exclusion, offering molecular-level insights for the design of 2D hybrid membranes for desalination.