Nitrogen-doped porous carbon for excellent CO₂ capture: A novel method for preparation and performance evaluation

Heteroatomic doped porous carbon (HPCs) is a promising advanced material, showing great application potential in greenhouse gas capture. Here, in-situ N-doped porous carbon (NPC) was developed via a novel and readily scalable strategy − one-step solvent-free melt polycondensation assisted by organic potassium salts, followed by pyrolysis and activation. As both a template and an activator, the added C₆H₅K₃O₇ played an important role to create abundant microporous structure. The as-fabricated NPC-650–0.5 showed a rich N content (6.11 at.%), abundant narrow micro-porosity (0.3437 cm³·g⁻¹), and a high surface area (1209.37 m²·g⁻¹) and delivered an excellent CO₂ static adsorption capacity (4.16 mmol·g⁻¹ and 8.40 mmol·g⁻¹ at 100 and 500 kPa), a fast adsorption kinetics (circa 98% of balance capacity in 12 min), moderate heat of adsorption (25 to 30 kJ/mol), high selectivity of CO₂/N₂, and outstanding uninterrupted recyclability. Both the narrow micropore volume and N-doping sites had strong effects on the CO₂ adsorption capacity, indicating a physical and chemical adsorption process with the mechanism being multi-layer adsorption by the micropore filling. This work highlights the great potential of the NPC-650–0.5 for capturing CO₂ and offers new insights into a green activator and a simple and easy-to-scale method for preparing HPCs.