Efficient carbon dioxide capture over a nitrogen-rich carbon having a hierarchical micro-mesopore structure

A nitrogen-rich carbon with a hierarchical micro-mesopore structure was obtained through pyrolysis of a porous polymer prepared from terephthalaldehyde and melamine, and then investigated for CO2 capture. This nitrogen-rich porous carbon exhibited a CO2 uptake of 141 mg/g at 25 °C, 1 atm, which is one of the highest CO2 capture capacities among carbon materials reported to date under these conditions. Excellent separation selectivity against N2 (CO2/N2 selectivity of ca. 32) was achieved. Also, fast adsorption–desorption kinetics were exhibited, and adsorbent regeneration was achieved by a simple helium purge at 25 °C. Ten consecutive adsorption–desorption test cycles established the material’s excellent stability as a CO2 adsorbent. These outstanding features as a CO2 adsorbent were mostly attributed to the material’s high content of basic nitrogen species, in addition to its physical properties (high surface area and hierarchical micro-mesoporosity).