Covalent triazine framework nanoribbons via polar Solvent-induced fragmentation for ultrafast and Solar-cleaning membrane separation

Abstract

Covalent triazine frameworks (CTFs) are drawing substantial interest as porous crystalline two-dimensional (2D) or three-dimensional (3D) nanomaterials. Fabrication of CTFs nanoribbon is challenging but appealing to separation and photocatalysis. Here we for the first time report the synthesis of crystalline CTF-1 nanoribbons (CTF-1-NR) comprising 2–3 covalent triazine framework units in width through a polar solvent-induced fragmentation strategy. The width of 1D nanoribbons can be facilely tuned by varying the solvent (e.g. ethanol) volume in trifluoromethanesulfonic acid layer after trimerization of aromatic nitriles. The CTF-1-NR are intercalated with Graphene oxide (GO) membranes to extend 1H NMR transverse relaxation time (T2) and enlarge the confined interspacing (∼8.8 Å), providing ultrafast water transport (∼60 L m-2h−1 bar−1) and high dye molecules rejection (98%). More significantly, the bridging CTF-1-NR enhances charge-carrier separation and gains superior solar-cleaning recoverable permeability (∼7 folds higher than GO). This study provides novel insight into the synthesis of crystalline COF nanoribbons and membrane separation.