Me–N–C (Me = Fe, Cu, and Co) nanosheet as a promising charge-controlled CO2 capture material

Abstract

It is necessary to explore advanced materials with high CO₂ selectivity and simple CO₂ regeneration to weaken the greenhouse effect. Therefore, in this study, we report a comprehensive investigation of CO₂, CH₄, H₂, C₂H₂, C₂H₄ and C₂H₆ on different Me–N–C nanosheets with different charge densities via density functional theory calculations. Our results demonstrate that CO₂ is weakly absorbed on neutral and positively charged Me–N–C monolayer, whereas CO₂ adsorption strength can be dramatically strengthened on a negatively charged Me–N–C monolayer, especially the Fe–N–C nanosheet. The adsorption energy of CO₂ on the negatively charged Fe–N–C nanosheet with a negative charge density of 15.27 × 10¹³ e⁻ cm⁻² is −3.07 eV, which is about 10 times larger than that (−0.283 eV) on neutral one; in addition, it also shows high CO₂ selectivity from mixtures containing CH₄, H₂, C₂H₂, C₂H₄ and C₂H₆. This investigation can provide valuable information for designing feasible adsorbent materials having high CO₂ adsorption capacity and selectivity.