Nitrogen Amelioration-Driven Carbon Dioxide Capture by Nanoporous Polytriazine

Nitrogen-enriched nanoporous polytriazines (NENPs) have been synthesized by ultrafast microwave-assisted condensation of melamine and cyanuric chloride. The experimental conditions have been optimized to tune the textural properties by synthesizing materials at different times, temperatures, microwave powers, and solvent contents. The maximum specific surface area (SA_BET) of 840 m² g^-1 was estimated in the sample (NENP-1) synthesized at 140 °C with a microwave power of 400 W and reaction time of 30 min. One of the major objectives of achieving a large nitrogen content as high as 52 wt % in the framework was realized. As predicted, the nitrogen amelioration has benefitted the application by capturing a very good amount of CO₂ of 22.9 wt % at 273 K and 1 bar. Moreover, the CO₂ storage capacity per unit specific surface area (per m² g^-1) is highest among the reported nanoporous organic frameworks. The interaction of the CO₂ molecules with the polytriazine framework was theoretically investigated by using density functional theory. The experimental CO₂ capture capacity was validated from the outcome of the theoretical calculations. The superior CO₂ capture capability along with the theoretical investigation not only makes the nanoporous NENPs superior adsorbents for the energy and environmental applications but also provides a significant insight into the fundamental understanding of the interaction of CO₂ molecules with the amine functionalities of the nanoporous frameworks.