Ordered 2D RUB-15 nanosheets with high loading in mixed matrix membranes for H₂/CO₂ separation

Mixed matrix membranes (MMMs) combining functional fillers with polymer matrices hold promise for high-efficiency separation. However, it remains a great challenge to enhance the loading to fully harness the capabilities of the fillers. Herein, we introduced RUB-15 nanosheets as fillers for MMMs to approach parallel alignment of nanosheets within the matrix, thus achieving a high-loading rate of up to 55 wt% and constructing fast and continuous mass transfer channels. The parallel orientation reduced the occurrence of defects, which played a critical role in enhancing separation. An optimized membrane with a 50 wt% loading rate exhibited exceptional H₂/CO₂ gas separation performance with H₂ permeability of 1934 Barrer and selectivity of 44.5, maintaining a separation factor of 16.7 at 125°C. This study maximizes the performance of porous functional fillers within the membrane by enhancing gas separation capabilities through the ordered alignment of nanosheets and provides valuable insights for future membrane development.