Nanoconfinement-enabled MXene-based membranes for synergistic swelling resistance and sustainable water purification

Weak intersheet interactions induce interlayer swelling in 2D MXene membranes, limiting their otherwise promising practical application in water purification. Herein, we developed an anti-swelling MXene-based membrane for water purification. Supramolecular hydrogen bonding between MXene and graphitic carbon nitride (CN) nanosheets enabled the formation of a tightly packed structure. Concurrently, covalent interactions involving polydopamine (PDA) and polyethyleneimine (PEI) enhanced cross-linking, which created a nanoconfined interlayer space to suppress swelling. Notably, the MXene/CN@PDA/PEI membrane maintained a stable interlayer spacing of 15.27 ± 0.08 Å even after 700 h of water immersion—outperforming most reported MXene-based membranes. Furthermore, its broad light absorption and narrow bandgap (~2.10 eV) enabled superior self-cleaning performance. In cyclic tests, it retained ~90.7 % flux recovery after 40 h, demonstrating that nanoconfinement effectively suppresses swelling and stabilizes active sites. This study presents an effective approach for developing high-performance MXene membranes featuring anti-swelling and self-cleaning capabilities, aimed at sustainable water purification.