Enhanced CO₂ Adsorption on Nitrogen-Doped Porous Carbons Derived from Commercial Phenolic Resin

The CO₂-capture potential of porous carbons that have been derived from phenolic resin and doped with nitrogen was assessed in this work. Using carbonized commercial phenolic resin as carbon precursors, a series of carbons have been synthesized using urea modification and KOH activation under different conditions. The activation temperature and mass ratio of KOH to precursor affected the CO₂ uptake capacity. These phenolic-resin-derived carbons show high CO₂ capture capacity, up to 4.61 mmol/g at 25 °C and 7.13 mmol/g at 0 °C under atmospheric pressure. The sample prepared under relatively mild conditions, i.e., activation temperature of 600 °C and mass KOH/precursor of 3, demonstrated the maximum CO₂ uptake capacity under ambient conditions. A systematic study shows that the synergetic effects of narrow microporosity and nitrogen content determine the sorbents’ capability to capture CO₂. In addition, the pore size and the narrow micropores’ distribution affect the CO₂ adsorption capacity of this series of porous carbons. Moreover, these resin-derived carbons show other superior CO₂ capture properties such as fast sorption kinetics, high CO₂/N₂ selectivity, moderate heat of adsorption, stable recyclability, and high dynamic CO₂ capture capacity.