Disulfide-mediated in-situ crosslinking of MXene membranes for enhanced stability and precise molecular sieving

MXene nanomaterials have emerged as promising materials for membrane design due to their distinctive chemical functionalities and tunable lamellar architecture. However, weak interlayer interactions between adjacent nanosheets often lead to membrane swelling and even redispersion in solvents, thereby compromising their performance in liquid separation. Although conventional crosslinking methods can alleviate these issues, they often cause an irreversible alteration of the interlayer spacing, which hinders precise molecular sieving. To address these challenges, we developed an in-situ disulfide crosslinking strategy for fabricating MXene membranes, in which chemical modification and crosslinking occur after membrane formation. As a result, the interlayer spacing of the crosslinked membrane remains virtually identical to that of the pristine membrane. Thanks to the crosslinked structure, the membranes maintain their structural integrity even under sonication. This well-defined microstructure enables size-selective molecular sieving capability. Moreover, leveraging the reversibility of disulfide bonds, the membrane exhibits excellent recyclability, achieving a nanosheet recovery rate of 88.4 %. This in-situ crosslinking strategy not only provides a sustainable pathway for advancing MXene-based membranes in water purification but also shows great potential for application with other two-dimensional materials to prepare high-performance membranes.