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 ZnCl2 under ionothermal conditions. The influence of several parameters such as the ZnCl2/monomer ratio and reaction temperature on the structure and porosity of the resulting frameworks was systematically examined. After a thorough characterization, their performance in H2 and CO2 adsorption as well as their selectivity of CO2 over N2 was assessed. Notably, the CTF obtained using 20 molar equiv of ZnCl2 at a reaction temperature of 400 °C (CTF-20-400) exhibits an excellent CO2 adsorption capacity of 3.48 mmol/g at 1 bar and 273 K as well as a significantly high H2 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 CO2/N2 selectivity (up to 36 at 298 K), making them promising adsorbents for gas sorption and separation.