Facile synthesis of inherently nitrogen-doped PAN-derived microporous carbons activated with NaNH₂ for selective CO₂ adsorption and separation

N-doped porous carbons (PCs) are extensively researched for CO₂ capture and separation under flue gas conditions, but their complex and expensive preparation methods hinder widespread industrial use. Herein, we present a direct approach for synthesizing N-doped PCs by utilizing polyacrylonitrile (PAN) and NaNH₂ as precursors, without the need for any solvents. The utilization of NaNH₂ as both a porogen and nitrogen supply during carbonization is primarily responsible for the formation of the well-developed pore structure and high specific surface area of N-doped PCs. The optimized sample “PN-3” demonstrated excellent textural features with an excellent specific surface area (SSA) of 2490 m²/g, a pore volume of 2.0559 cm³/g, a well-defined pore size distribution (PSD), and abundant micropores (<1 nm). In addition, PN-3 has the highest pyrrolic nitrogen content (∼40.1 at.%), resulting in a significant capacity for CO₂ adsorption (7.15 mmol/g at 273 K/1bar, 4.56 mmol/g at 298 K/1 bar, 26.2 mmol/g at 298 K/ 40 bar). Furthermore, it exhibits an outstanding CO₂/N₂ selectivity (∼102) based on the ideal adsorbed solution theory (IAST) at 273 K, surpassing the performance of most of previously reported biomass and polymer-derived N-doped carbons in terms of CO₂ adsorption and separation. In addition, the adsorption process is characterized by a modest heat of adsorption (39.10 kJ/mol) and a steady cyclic pattern of CO₂ adsorption–desorption under flue gas settings (15 % CO₂ and 85 % N₂). This indicates that the adsorption is mostly governed by physisorption, which allows for an energy-efficient regeneration process. In summary, this study showcases the successful production of highly PCs that can effectively adsorb CO₂, enlightening the way toward establishment of a cost-effective and facile synthetic protocol for achieving CO₂ capture/separation at the commercial scale.