Structure regulation of two-dimensional lamellar NH2-UIO-66@MXene membrane for efficient H2/CO2 separation

Abstract

Two-dimensional membranes are considered the next generation separation membrane with great application potential due to their excellent separation performance, good mechanical strength and thermal stability compared with traditional membrane materials. In this work, the flexible NH2-UIO-66@MXene membrane was successfully prepared for gas separation by loading NH2-UIO-66 particles onto Ti3C2 nanosheets based on an in-situ growth strategy. A LiF-HCl mixed solution was used as the etchant to obtain the Ti3C2 nanosheets. The loading of NH2-UIO-66 particles can regulate the interlayer spacing of Ti3C2 nanosheets, improving the specific surface area of Ti3C2 and the adsorption capacity for specific gases. The -NH2 group in NH2-UIO-66 enabled preferential adsorption of CO2 over H2, and the CO2 molecules adsorbed in the channel can even block the molecules passing through, increasing the resistance of CO2 diffusion. As a result, the NH2-UIO-66@Ti3C2 hybrid membrane realizes the selective separation of H2/CO2 mixed gas, and the separation selectivity is as high as 155. The gas separation selectivity and permeation of the final prepared NH2-UIO-66@MXene were enhanced and exceeded the upper limit of Robeson upper bound (2017).

Keywords

• MXene
• NH2-UIO-66
• Structural regulation
• Flexible membrane
• Gas separation