Chemical activation of covalent triazine frameworks for gas storage

Abstract

Rational design of new 2D layered carbonaceous materials thanks to their excellent intriguing properties, such as highly tunable surface area, outstanding electrical conductivity, good chemical stability and excellent mechanical properties have become a major research focus in the field of material science. Also the introduction of heteroatoms, i.e., nitrogen, into the 2D carbon nanomaterials has proven to be highly effective to extend its application to gas storage, energy conversion and storage, fuel cells and heterogeneous catalysis. In this work 2D layered covalent triazine frameworks by using the “bottom-up approach”, was synthesized. And by developing micropores in the frameworks by chemical activation method for the first time in detail at temperatures of $500-900^\circ C$. It is found that the twofold enhancement of surface area and dominant formation of micropores in the CTF-1 and CTF-2 material at the activation temperature of $700^\circ C$. Such a highly microporous activated CTF-1 and CTF-2 having extremely high specific area shows largely enhanced gas adsorption properties with $CO_2$ uptake capacities up to 6.0 $mmol g^{-1}$ at 1 bar, 273 K along with a isosteric heats of adsorption ($Q_{st}$) of 26.4 for CTF-1-700 and CO2 uptake capacities up to 6.0 $mmol g^{-1}$ at 1 bar, 273 K along with a isosteric heats of adsorption ($Q_{st}$) of 26.3 for CTF-2-700. In addition, H2 uptake capacity of 2.46 and 1.66 wt% at 77 and 87 K, 1bar and the $Q_{st}$ value of 10.95 $kJ mol^{1}$ at zero coverage have been also observed.