Graphene oxide (GO) membranes have received considerable attention owing to their outstanding water-permeation properties; however, the effect of the membrane’s microstructures (such as the distribution of oxidized and pristine regions) on the transport mechanism remains unclear. In this study, we performed molecular simulations to explore the permeation of a water-ethanol mixture using a new type of Janus GO membranes with different orientations of oxidized and pristine surfaces. The results indicate that the oxidized upper surface endows the GO membrane with considerable water-capture capability and the in-built oxidized interlayer promotes the effective vertical diffusion of water molecules. Consequently, using the optimized Janus GO membrane, infinite water selectivity and outstanding water flux (∼40.9 kg·m⁻²·h⁻¹) were achieved. This study contributes to explaining the role of oxidized regions in water permeation via GO membranes and suggests that Janus GO membranes could be used as potential candidates for water-ethanol separation.

氧化石墨烯（GO）膜由于其出色的透水性而受到了广泛的关注。然而，膜的微结构（如氧化和原始区域的分布）对转运机制的影响尚不清楚。在这项研究中，我们进行了分子模拟，以探索使用氧化和原始表面取向不同的新型Janus GO膜渗透水-乙醇混合物的过程。结果表明，氧化的上表面赋予GO膜相当大的吸水能力，而内置的氧化中间层则促进了水分子的有效垂直扩散。因此，使用优化的Janus GO膜可实现无限的水选择性和出色的水通量（〜40.9 kg·m ^-2·h ^-1）。这项研究有助于解释氧化区域在通过GO膜的水渗透中的作用，并建议Janus GO膜可用作水-乙醇分离的潜在候选物。