Nitrogen and oxygen-codoped microporous carbon derived from acid-base interaction of carboxylic acid polymers and urea for enhanced CO₂capture

Nitrogen and oxygen-codoped microporous carbon was prepared using carboxylic acid polymer (PDVH) with urea as precursor. Due to the acid-base interaction, urea was trapped on the surface of the precursor, enhancing of the specific surface area, the nitrogen content and pore volume of the porous carbon after carbonization. Among these materials, the PDVH-NC-2.0 obtained an uptake of CO2 to 3.05 mmol g-1 at 25 °C and 1 atm. Meanwhile, the CO2 adsorption selectivity of these PDVH-NC-X ranged from 21.3 to 30.4 (CO2/N2 =85:15) based on the IAST adsorbed solution theory, resulting from the increased amount of the pyrrolic-N and oxidized-N, which enhanced the adsorption selectivity of CO2. Furthermore, the weak interaction involving N sites with CO2 should be responsible for the improvement of the uptake of CO2 through electrostatic potential mapping (ESP) and interaction region indicator (IRI). Finally, the CO2 uptake of the PDVH-NC-2.0 was still maintained after five cycles of reuse, which meant this porous carbon would be superior alternative for CO2 capture.