文摘
A series of nitrogen-doped microporous carbons (NCs) was successfully prepared by direct pyrolysis of high-surface-area microporous imine-linked polymer (ILP, 744 m2/g) which was formed using commercial starting materials based on the Schiff base condensation under catalyst-free conditions. These NCs have moderate specific surface areas of up to 366 m2/g, pore volumes of 0.43 cm3/g, narrow micropore size distributions, and a high density of nitrogen functional groups (5.58鈥?.74%). The resulting NCs are highly suitable for CO2 capture adsorbents because of their microporous textural properties and large amount of Lewis basic sites. At 1 bar, NC-800 prepared by the pyrolysis of ILP at 800 掳C showed the highest CO2 uptakes of 1.95 and 2.65 mmol/g at 25 and 0 掳C, respectively. The calculated adsorption capacity for CO2 per m2 (渭mol of CO2/m2) of NC-800 is 7.41 渭mol of CO2/m2 at 1 bar and 25 掳C, the highest ever reported for porous carbon adsorbents. The isosteric heats of CO2 adsorption (Qst) for these NCs are as high as 49 kJ/mol at low CO2 surface coverage, and still 25 kJ/mol even at high CO2 uptake (2.0 mmol/g), respectively. Furthermore, these NCs also exhibit high stability, excellent adsorption selectivity for CO2 over N2, and easy regeneration and reuse without any evident loss of CO2 adsorption capacity.
Keywords:
microporous carbon; nitrogen doping; CO2 capture; adsorption and separation