Harmonizing Between Chemical Functionality and Surface Area of Porous Organic Polymeric Nanotraps for Tuning Carbon Dioxide Capture.

Abstract

Two hydroxy rich hypercrosslinked POPs, namely Ph/Tt-POP have been developed by facile one-pot condensation polymerization strategy. The high surface areas of both the Ph/Tt-POP (1057 and 893 m2g-1, respectively), and the heteroatom functionality in the POP framework instigated us to explore our material for CO2 adsorption study. The CO2 uptake capacities in Ph/Tt-POP are found to be 2.45 and 2.2 mmol g-1, at 273 K respectively. in-situ static 13C NMR experiment shows that CO2 molecules in Tt-POP appear to be less mobile than those in Ph-POP which probably due to the presence of triazine functional groups along with high abundant -OH groups in the Tt-POP framework. An in-depth study of the CO2 adsorption mechanism by density functional theory (DFT) calculations also shows that CO2 adsorption at the cages formed by two benzyl rings represents the most stable interaction and CO2 molecule is more favorably adsorbed on the Ph-POP with the more negative interaction energies values compared to that of Tt-POP. Non-covalent interaction (NCI) plot revealed that CO2 molecule is adsorbed more on the Ph-POP than Tt-POP, which can be explained by hydrogen bond formation in case of Tt-POP repeating units turning aside CO2 molecule to interact with the Ph component.