Straightforward preparation of fluorinated covalent triazine frameworks with significantly enhanced carbon dioxide and hydrogen adsorption capacities

Abstract

The development of advanced functional porous materials for efficient carbon capture and separation is of prime importance with respect to energy and environmental sustainability and employing covalent triazine frameworks as the adsorbents for carbon capture is deemed to be one of the most promising means to alleviate this issue. Herein, we report the construction of a set of partially fluorinated microporous covalent triazine frameworks (FCTFs) with appropriate CO₂-philic functionalities (N and F) and high porosities (up to 2060 m² g⁻¹) for effective gas adsorption and separation. Markedly, the CO₂ adsorption capacity of the FCTF materials prepared at a ZnCl₂/monomer ratio of 20 and 400 °C reaches up to 4.70 mmol g⁻¹ at 273 K and 1 bar, which is among the top level of all the reported CTFs. In addition, the studied FCTFs also exhibit a significantly high H₂ uptake of 1.88 wt% at 77 K and 1 bar, outperforming most of the reported CTF materials under identical conditions. Apart from this, the obtained FCTF materials also display moderate CO₂ selectivities over N₂ (28) and CH₄ (5.6) at room temperature.