Imine-Linked Polymer Based Nitrogen-Doped Porous Activated Carbon for Efficient and Selective CO₂ Capture

The preparation of nitrogen-doped activated carbon (NACs) has received significant attention because of their applications in CO₂ capture and sequestration (CCS) owing to abundant nitrogen atoms on their surface and controllable pore structures by carefully controlled carbonization. We report high-surface-area porous N-doped activated carbons (NAC) by using soft-template-assisted self-assembly followed by thermal decomposition and KOH activation. The activation process was carried out under different temperature conditions (600-800 °C) using polyimine as precursor. The NAC-800 was found to have a high specific surface area (1900 m² g^-1), a desirable micropore size below 1 nm and, more importantly, a large micropore volume (0.98 cm³ g^-1). NAC-800 also exhibits a significant capacity of CO₂ capture i.e., over 6. 25 and 4.87 mmol g^-1 at 273 K and 298 K respectively at 1.13 bar, which is one of among the highest values reported for porous carbons so far. Moreover, NAC also shows an excellent separation selectivity for CO₂ over N₂.