Newly Designed Covalent Triazine Framework Based on Novel N-Heteroaromatic Building Blocks for Efficient CO₂ and H₂ Capture and Storage

In this article, a set of novel covalent triazine frameworks (CTFs) were prepared by trimerization of 4,4′,4″,4‴-(1,4-phenylenebis(pyridine-4,2,6-triyl))tetrabenzonitrile in molten ZnCl 2 under ionothermal conditions. The influence of several parameters such as the ZnCl 2 /monomer ratio and reaction temperature on the structure and porosity of the resulting frameworks was systematically examined. After a thorough characterization, their performance in H 2 and CO 2 adsorption as well as their selectivity of CO 2 over N 2 was assessed. Notably, the CTF obtained using 20 molar equiv of ZnCl 2 at a reaction temperature of 400 °C (CTF-20-400) exhibits an excellent CO 2 adsorption capacity of 3.48 mmol/g at 1 bar and 273 K as well as a significantly high H 2 uptake of 1.5 wt % at 1 bar and 77 K. These values belong to the top levels for all the CTFs measured under identical conditions to date. In addition, the obtained CTFs also present a relatively high CO 2 /N 2 selectivity (up to 36 at 298 K), making them promising adsorbents for gas sorption and separation.