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

Abstract

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.