Ultra-microporous N-doped carbon from polycondensed framework precursor for CO2 adsorption

High adsorption capacity and selectivity of microprous carbon are critical for exceptional post-combustion CO2 capture ability. Herein we report a novel strategy to prepare N-doped microprous carbon with high surface area (2363 m2 g−1 for CPTHB-7), narrow pore size distribution and high ultramicropore ratio (<0.7 nm, 68% for CPTHB-6) via a simple chemical activation of a rigid polymer porous framework (PTHB) synthesized via polycondensation reaction of 1,3,5-THB and aniline. The as-prepared microprous carbon exhibit high CO2 adsorption capacities of 5.6–6.3 mmol g−1 (273 K and 1 bar) and sufficient CO2/N2 selectivity of 12–22 for a 0.15/0.85 CO2/N2 mixture at 298 K and 1 bar (conditions of CO2 capture application). The effect of microporosity and N content for our materials on the CO2 adsorption performance had also been investigated. Microporous volume below critical size contributed to the adsorption capacity for CO2, while the N content and nitrogen species play a role in the CO2/N2 selectivity.