Self-crosslinked MXene hollow fiber membranes for H₂/CO₂ separation

Inorganic hollow fibers are promising substrates for the scaled-up fabrication of two-dimensional (2D) material membranes because of their high packing density and durability under harsh application conditions. However, the inefficient stacking of 2D materials (e.g., MXene nanosheets) on hollow fibers usually leads to oversized interlayer spaces, resulting in low molecular sieving performance. In this study, self-crosslinked MXene hollow fiber membranes were fabricated using a facile thermal treatment process. The self-crosslinking process was documented in detail. An in-situ thermogravimetric analyzer–Fourier transform infrared spectra measurement revealed that the early thermal treatment stage dominated the self-crosslinking process and controlled the regulation of MXene interlayer spacing. The self-crosslinked MXene hollow fiber membranes prepared in this manner exhibited a H₂ permeance of 70.6 GPU and H₂/CO₂ selectivity of 30.3, with good operation stability for more than 120 h. This work demonstrates that the self-crosslinking strategy is an efficient approach for improving the size-sieving properties of 2D MXene membranes.