Superior Selective CO₂ Adsorption and Separation over N₂ and CH₄ of Porous Carbon Nitride Nanosheets: Insights from GCMC and DFT Simulations

Abstract

Development of high-performance materials for the capture and separation of CO2 from the gas mixture is significant to alleviate carbon emission and mitigate the greenhouse effect. In this work, a novel structure of C9N7 slit was developed to explore its CO2 adsorption capacity and selectivity using Grand Canonical Monte Carlo (GCMC) and Density Functional Theory (DFT) calculations. Among varying slit widths, C9N7 with the slit width of 0.7 nm exhibited remarkable CO2 uptake with superior CO2/N2 and CO2/CH4 selectivity. At 1 bar and 298 K, a maximum CO2 adsorption capacity can be obtained as high as 7.06 mmol/g, and the selectivity of CO2/N2 and CO2/CH4 was 41.43 and 18.67, respectively. In the presence of H2O, the CO2 uptake of C9N7 slit decreased slightly as the water content increased, showing better water tolerance. Furthermore, the underlying mechanism of highly selective CO2 adsorption and separation on the C9N7 surface was revealed. The closer the adsorption distance, the stronger the interaction energy between the gas molecule and the C9N7 surface. The strong interaction between the C9N7 nanosheet and the CO2 molecule contributes to its impressive CO2 uptake and selectivity performance, suggesting that the C9N7 slit could be a promising candidate for CO2 capture and separation.

Adsorption Mechanisms of CO2 on Macroporous Ion-Exchange Resin Organic Amine Composite Materials by the Density Functional Theory

“…The results indicate that the adsorption of CO 2 on MCER and D001 is simple physical adsorption, and this is consistent with the experimental data that the adsorption capacity of CO 2 on MCER (1.87 mmol/g) is greater than that of CO 2 on D001 (1.07 mmol/g). , The adsorption energies of the CO 2 molecules in MCER-DEA and D001-PEI are −17.59 and −18.64 kcal/mol, respectively. These values are close to B 38 fullerene (−15.96 kcal/mol) and Ni-decorated InN (−15.22 kcal/mol) but greater than the results of C 9 N 7 (−6.46 kcal/mol) and Se-doped graphene (−5.01 kcal/mol) . Considering that the E ads of CO 2 on a high-performance adsorbent are preferably between −9.78 kcal/mol and −19.57 kcal/mol, the MCER-DEA and D001-PEI are thus effective CO 2 storage adsorbents.…”

Molecular Simulation of Adsorption Separation of CO2 from Combustion Exhaust Mixture of Commercial Zeolites

“…There are many different components in actual combustion products such as H 2 O, SO 2 and NO X . Aside from the toxicity itself, these gases also have strong interactions with sorbents, decreasing the CO 2 capture capacity of the sorbent over subsequent cycles [4][5][6][7][8][9][10][11]. Rege et al [12] found that the presence of water could reduce the adsorption capacity in the adsorption process because of its strong adsorption force.…”