One-pot carbonization enrichment of nitrogen in microporous carbon spheres for efficient CO2 capture

Abstract

Nitrogen-enriched porous carbon spheres are synthesized through a one-pot carbonization process by decorating the as-made melamine–formaldehyde spheres with resorcinol and hexamethylenetetramine, exhibiting high surface areas of 518–828 m² g⁻¹ with a micropore size of 0.5–1.3 nm. Due to the successful incorporation of large amounts of highly dispersed N (4.3–10.8 wt%) into the carbon matrix, the synthesized microporous carbon spheres, having a large amount of narrow micropores (<1.0 nm), show a good capacity to store CO₂. At 1 atm, the equilibrium CO₂ capture capacities of the obtained microporous carbons are in the range of 4.0–5.4 mmol g⁻¹ at 0 °C and 3.0–4.3 mmol g⁻¹ at 25 °C, revealing their great promise for practical CO₂ capture applications. More importantly, the CO₂ uptake as large as 2.76 mmol g⁻¹ can be obtained at 75 °C, suggesting the significant promise of the synthesized carbon materials for CO₂ capture and separation.