Assembly of 2D MXene nanosheets and TiO₂ nanoparticles for fabricating mesoporous TiO₂-MXene membranes

A simple and scalable method was proposed for the preparation of mesoporous membranes by assembling two-dimensional (2D) MXene nanosheets and TiO₂ nanoparticles (NPs) on a macroporous support. MXene nanosheets were introduced into TiO₂ hydrosol, and then the sol was transformed into gel for fabrication of mesoporous TiO₂-MXene membranes. Characterization results confirmed that an assembled structure of TiO₂-MXene nanosheets was formed, benefiting from the nanosheets as ‘floor tiles’ thereby successfully inhibited the sol infiltration to the porous support. As a result, the hydrosols could be directly coated on macroporous substrates (with only one single cycle of aging and calcination) such as a disc support with an average pore size of ~100 nm and a four-channel hollow fiber with an average pore size of ~ 00 nm. Filtration experiments revealed the resulted membranes, in particular of the hollow fiber TiO₂-MXene membranes, had a narrow pore size distribution, desirable rejection characteristics of dextran and high water permeate flux. The 2D nanosheet assisted TiO₂ NPs assembly proposed in this work promises a simple, feasible and scalable approach for fabricating high-performance mesoporous TiO₂ membranes.