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.