Molecular simulation on carbon dioxide capture performance for carbons doped with various elements

Among the different types of CO₂ capture technologies for post-combustion, sorption CO₂ capture technology with carbon-based sorbents have been extensively explored with the purpose of enhancing their sorption performance by doping hetero elements due to the rapid reaction kinetics and low costs. Herein, sorption capacity and selectivity for CO₂ and N₂ on carbon-based sorbents doped with elements such as nitrogen, sulfur, phosphorus, and boron, are evaluated and compared using the grand canonical Monte Carlo (GCMC) method, the universal force field (UFF), and transferable potentials for phase equilibria (TraPPE). The sorption capacities of N-doped porous carbons (PCs) at 50 °C were 76.1%, 70.7%, 50.6%, and 35.7% higher than those of pure PCs, S-doped PCs, P-doped PCs, and B-doped PCs, respectively. Its sorption selectivity at 50 °C was approximately 14.0, nearly twice that of pure PCs or other hetero-element-doped PCs. The N-doped PCs showed the largest sorption heat at 50 °C among all the PCs, approximately 20.6 kJ·mol⁻¹, which was 9.7%−25.5% higher than that of the pure PCs under post-combustion conditions. Additionally, with the product purity of 41.7 vol.%−75.9 vol.% for vacuum pressure swing sorption, and 53.4 vol.%−83.6 vol.% for temperature swing sorption, the latter is more suitable for post-combustion conditions than pressure-swing sorption.