Nitrogen-doped porous carbon prepared from a liquid carbon precursor for CO2 adsorption

We report a new carbonaceous material derived from a liquid precursor, polyethylenimine (PEI) by chemical activation using KOH. The PEI-derived activated carbon possesses typical microporosity with a high specific surface area. It also features rich nitrogen content and various nitrogen functional groups. It was found that at 1 bar the CO2 uptake of these PEI-derived carbons was 4.9–5.7 mmol g−1 at 0 °C and 2.9–3.7 mmol g−1 at 25 °C. Specifically, the CO2 adsorption capacity of the carbon activated at 600 °C was the highest, being 5.67 mmol g−1 at 0 °C, atmospheric conditions. The PEI-derived carbons also exhibit very good stability during multi-cycle adsorption–desorption tests and a high selectivity of CO2 over N2 at 25 °C.