Iron Nanoclusters as Template/Activator for the Synthesis of Nitrogen Doped Porous Carbon and Its CO₂ Adsorption Application

We propose a facile synthesis approach for nitrogen doped porous carbon and demonstrate a novel pore-forming method that iron nanoclusters act as a template or activator at different carbonization temperatures based on Fe³⁺-poly(4-vinyipyridine) (P4VP) coordination. P4VP will completely decompose even in an inert atmosphere, but under the coordination and catalysis of Fe³⁺, it can be converted to carbon at a very low temperature (400 °C). The aggregation of iron nanoclusters in the carbonization process showed different pore-forming methods at different temperatures. The as-prepared materials possess high specific surface area (up to 1211 m² g^-1), large pore volume (up to 0.96 cm³ g^-1), narrow microporosity, and high N content (up to 9.9 wt %). Due to these unique features, the materials show high CO₂ uptake capacity and excellent selectivity for CO₂/N₂ separation. The CO₂ uptake capacity of NDPC-2-600 is up to 6.8 and 4.3 mmol g^-1 at 0 and 25 °C; the CO₂/N₂ (0.15/0.85) selectivity at 0 and 25 °C also reaches 18.4 and 15.2, respectively.