Hydrogen-Bonded\nUltrathin Porous Polyamide Membrane\nfor High Flux H<sub>2</sub>/CO<sub>2</sub> Separation

High-performance polymer-based H<sub>2</sub>/CO<sub>2</sub> separation\nmembranes are attractive for sustainable blue hydrogen production.\nHowever, achieving high-flux separation remains a challenge, as H<sub>2</sub> and CO<sub>2</sub> have similar diffusion rates within the\npolymer. In this work, hydrogen-bonded polyamide (PA) network membranes\nare synthesized through interfacial polymerization involving Tröger’s\nbase diamine (TBDA) and 1,3,5-benzenetricarbonyl trichloride, aiming\nto enhance the efficiency of H<sub>2</sub>/CO<sub>2</sub> separation.\nIncorporating the contorted TBDA unit into the PA structure enhances\nmicroporosity, which, in turn, boosts the H<sub>2</sub> permeance\nof the PA membrane. Notably, the presence of numerous intermolecular\nhydrogen bonds between N atoms in the TBDA and H atoms in the amide\ngroups helps to restrict the pore size further, thereby improving\nthe H<sub>2</sub>/CO<sub>2</sub> selectivity of the membrane. The\nresulting PA membrane demonstrates an outstanding H<sub>2</sub>/CO<sub>2</sub> selectivity of 23.5, coupled with a high H<sub>2</sub> permeance\nof 160 gas permeation unit (GPU), significantly exceeding the current\nupper bound. Additionally, our PA membranes maintain a stable H<sub>2</sub>/CO<sub>2</sub> selectivity of approximately 21.5 and a H<sub>2</sub> permeance of around 160 GPU over 100 h, indicating excellent\nlong-term stability. These findings suggest that the development of\nsuch advanced polymer membranes could pave the way for more efficient\nand sustainable blue hydrogen production, overcoming existing limitations\nin gas separation technologies.