Dual Strategic Approach to Prepare Defluorinated Triazole-Embedded Covalent Triazine Frameworks with High Gas Uptake Performance

A dual strategic approach has been adopted via judicious design and synthesis of a new triazole-substituted perfluorinated aromatic nitrile (Tz-PFCN) building block to prepare three defluorinated triazole-embedded covalent triazine frameworks (Tz- df -CTFs) via ZnCl 2 -catalyzed ionothermal process for high-capacity capture of small gases, especially CO 2, H 2, and CH 4 . Our approach combines the incorporation of both thermally sacrificial fluorine functionality as the origin of abundant microporosity and multi-N-containing triazole functionality as strong CO 2 -philic unit into the building block, which integrates high surface area (up to 2106 m 2 g –1 ) and pore volume (up to 1.43 cm 3 g –1 ) largely dominated (>90%) by narrow- and ultra-micropores together with high nitrogen and oxygen heteroatom content in the resulted Tz- df -CTF materials. The high microporosity in Tz- df -CTFs is mainly generated through the in situ defluorination process of the perfluorinated Tz-PFCN building block during the ionothermal process, and pore surfaces embedded with CO 2 -philic basic N-active sites as both triazole and triazine moieties confer the frameworks with the highest amount of CO 2 capture (7.65 mmol g –1 at 273 K, 1 bar) and H 2 storage (2.91 wt % at 77 K, 1 bar) capability among all known porous organic polymers, including CTF systems, till date. The methane uptake capacity (4.41 wt % at 273 K, 1 bar) of these materials ranks second highest as well. A breakthrough simulation shows good separation of CO 2 /N 2 (flue gas composition) and CO 2 /CH 4 binary gas mixture in Tz- df -CTFs under industrial fixed-bed operational conditions. We anticipate that this unique dual approach will allow new opportunities toward designing and synthesizing of novel high-performing nanoporous sorbents for task-specific applications in the domain of clean energy and environmental fields.