Influence of Fe-N co-doping on biochar on the adsorption of CO2

Carbonaceous materials have been widely studied as CO₂ adsorbents in recent years. Fe/N doping can enhance the surface interactions between carbon materials and pollutants. In this study, the influence of Fe-N co-doping on biochar on the adsorption of CO₂ was investigated in experimental and theoretical. The results of characterization revealed that Fe-N co-doping altered the pore structure and the aromaticity of the carbon material. Additionally, the introduction of nitrogen promoted the dispersion and anchoring of iron on the carbon surface. Fe-N co-doped biochar exhibited a maximum CO₂ adsorption capacity of 3.58 mmol/g (1 bar, 298 K). Theoretical calculations indicated that Fe-N co-doping facilitated electron transfer between the carbon substrate and CO₂, enhanced π–π stacking interactions, and strengthened the Lewis acid-base interactions between the substrate and CO₂. Among all the adsorption sites, Fe site on the Fe-N-doped substrate demonstrated the highest adsorption energy for CO₂ (−58 kJ/mol). Therefore, the Fe-N co-doping significantly enhanced the CO₂ adsorption capacity of carbon materials by 16.23 % compared with DBC, offering valuable insights for the development of novel and efficient carbon-based materials for CO₂ capture.