Graphene Oxide‐Carbon Nanotube Hybrid Membranes for High‐Pressure and High‐Flux Nanofiltration

Abstract Graphene oxide (GO) membranes are promising candidates to revolutionize nanofiltration, due to their atomic thickness and ultrafast water transport. Yet their practical use is hindered by structural damage under high pressure. Conventional strategies like thickening membranes, reducing interlayer spacing, or cross‐linking nanosheets improve pressure resistance but significantly reduce water permeability to impractical levels (e.g., 0.15 L m −2 h −1 bar −1 at 60 bar). Here, this dilemma is addressed by designing ultrathin GO/carbon nanotube (CNT) hybrid membranes. The CNT network reinforces the stacked GO nanosheets by reducing their free‐standing diameter while increasing membrane thickness and Young's modulus. The pressure resistance is achieved up to 60 bar, triple that of the pristine GO membranes. A maximum water flux of 966 ± 96 L m −2 h −1 is achieved by a 68 nm thick GO/CNT membrane with optimal GO nanosheet size and CNT loading amount, facilitating 1–3 orders of magnitude higher water flux per unit membrane thickness than all available membranes. This breakthrough resolves the critical trade‐offs among pressure resistance, flux, and membrane thickness, marking a transformative leap in GO‐based nanofiltration efficiency. The innovation holds immediate potential for applications in sustainable water remediation, pharmaceuticals, energy storage, and electronics.