Tian Xiaohe, Cao Li, Zhang Keming, Zhang Rui, Li Xueqin, Yin Chongshan, Wang Shaofei
College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, China.
State Key Laboratory of Petroleum Pollution Control, Beijing, 102206, China.
Angew Chem Int Ed Engl. 2025 Jan 21;64(4):e202416864. doi: 10.1002/anie.202416864. Epub 2024 Nov 7.
Covalent organic frameworks (COFs) exhibit considerable potential in gas separations owing to their remarkable stability and tunable pore structures. Nevertheless, their application as gas separation membranes is hindered by limited size-sieving capabilities and poor processability. In this study, we propose a novel molecular weaving strategy that combines hydroxyl polymers and 2D TpPa-SOH COF nanosheets, achieving high gas separation efficiency. Driven by the strong electrostatic interactions, the hydroxyl chains thread through the COF pores, effectively weaving and assembling the composites to achieve exceptional flexibility and high mechanical strength. The penetrated chains also reduce the effective pore size of COFs, and combined with the "secondary confinement effect" stemming from abundant CO sorption sites in the channels, the PVA@TpPa-SOH membrane demonstrates a remarkable H permeance of 1267.3 GPU and an H/CO selectivity of 43, surpassing the 2008 Robson upper bound limit. This facile strategy holds promise for the manufacture of large-area COF-based membranes for small-sized gas separations.
共价有机框架材料（COFs）因其卓越的稳定性和可调节的孔结构，在气体分离方面展现出巨大潜力。然而，其作为气体分离膜的应用受到尺寸筛分能力有限和加工性能差的阻碍。在本研究中，我们提出了一种新颖的分子编织策略，将羟基聚合物与二维TpPa-SOH COF纳米片相结合，实现了高效的气体分离。在强静电相互作用的驱动下，羟基链穿过COF孔，有效地编织并组装复合材料，从而获得出色的柔韧性和高机械强度。穿透的链还减小了COFs的有效孔径，再结合通道中丰富的CO吸附位点所产生的“二次限制效应”，PVA@TpPa-SOH膜展现出1267.3 GPU的显著H渗透率和43的H/CO选择性，超过了2008年罗布森上限。这种简便的策略有望用于制造用于小型气体分离的大面积COF基膜。
