Room-temperature in situ synthesis of MOF@MXene membrane for efficient hydrogen purification

MXene-based membranes with well-defined nanochannels are promising for gas separation. However, manipulating the interlayer structure to obtain high permeance and selectivity remains a great challenge. Herein, we report the construction of MOF@MXene membrane with significantly enhanced gas permeance and selectivity using room-temperature in situ synthesized MOF-801@MXene nanosheets as building blocks. Specifically, negatively charged MXene nanosheets can anchor Zr-metal ions from the surrounding through electrostatic interaction, and then coordinate with ligands at room temperature, yielding MOF-801 crystals with a particle size of approximately 20 nm uniformly grown on the MXene nanosheets. The membranes were then fabricated by vacuum filtration of the as-synthesized MOF-801@MXene nanosheets on the surface of porous organic substrate. The physicochemical properties of the as-synthesized MOF-801@MXene nanosheets and corresponding membranes were observed by XPS, AFM, SEM, IR, XRD, and gas adsorption analysis. Because the MOF-801 crystals can provide more transport channels for H₂ molecules and exhibit high adsorption capacity for CO₂ molecules to impede its diffusion, the resulting membranes display excellent gas separation performance with a H₂ permeance of 2200 GPU and H₂/CO₂ selectivity of 26.6. Such a facile preparation method for MOF@MXene membranes could provide valuable insights into the development of advanced materials for molecular separation.