Heterostructured MXene/COF nanofiltration membranes: Synergistic enhancement via interlayer spacing and penetrating pores

Nanofiltration holds significant potential for mitigating water scarcity, yet reconciling high selectivity with efficient mass transfer remains a critical challenge. MXene membranes enable precise molecular sieving through interlayer spacing, while covalent organic framework (COF) membranes leverage penetrating pores for rapid mass transfer. However, MXene membranes suffer from restricted permeability and structural instability, whereas COF membranes face limitations in achieving small-sized pores and compromising sieving efficiency. Herein, we fabricate a heterostructured MXene/COF membrane by synergistically manipulating interlayer spacing of MXene with penetrating pores of COF via sequential vacuum-assisted self-assembly. Matched surface hydrophilicity and electrostatic property between MXene and COF render robust interfacial adhesion. The optimal MXene/COF membrane exhibits a water permeance of 356.6 ± 24.1 L m −2 h −1 bar −1 and a CR rejection of 99.8 %, along with excellent operational stability during 48-hour continuous filtration. The MXene/COF membrane opens a novel avenue for fabricating versatile heterostructured membranes for advanced separations.