A study combining DFT and molecular dynamics simulations into the performance of B6N6 nanosheets for CO2 capture and separation

In this work, we chiefly deal with the uptake and the capture of CO2 gas by the B6N6 monolayer via periodic density functional theory. Based on the results, the unit cell of the B6N6 sheet can take up nine CO2 molecules with a CO2 capture capacity of 73 wt%. Average adsorption energy for the 1CO(2)/B6N6, 2CO(2)/B6N6, 3CO(2)/B6N6, 4CO(2)/B6N6, 5CO(2)/B6N6, and 9CO(2)/B6N6 complexes are - 3.163, - 1.649, - 1.191, - 0.972, - 0.834, and - 0.574 eV/CO2, respectively. Mulliken charge values on the CO2 gas show that the B6N6 nanosheet has transferred charge to the gases. The results indicate that a pristine B6N6 sheet, due to the stronger adsorption of CO2 over the surface compared to other gases, can selectively capture CO2 instead of N-2, H-2, and CH4 gases in the air. The structural and thermal stability of the pristine B6N6 substrate and 9CO(2)/B6N6 complex at 300 K has been proven by utilizing molecular dynamics analysis. The electron density difference has also been used to investigate the physical or chemical interaction between CO2 molecules and the substrate. The present study results introduce pristine B6N6 substrate as an investible substrate for highly efficient CO2 capture and separation.