Tailoring microporosity and nitrogen content in carbons for achieving high uptake of CO2 at ambient conditions

Abstract

A series of nitrogen-containing carbon spheres (CS) was prepared using the modified Stober method. These CS were synthesized by using resorcinol and formaldehyde as carbon precursors, melamine as nitrogen precursor and ammonia as a polymerization reaction catalyst. Hydrothermal treatment followed by activation of these polymer spheres resulted in highly porous nitrogen-containing CS. Elemental analysis and N2 adsorption showed that the aforementioned CS exhibited high surface area (reaching 1,610 m2/g) with large fraction of fine micropores (volume of micropores smaller than 1 nm was estimated to be 0.40 cm3/g) and comparatively high nitrogen content (about 4.0 at.%). Interestingly, high CO2 adsorption capacities, 4.4 and 6.9 mmol/g, were obtained for these CS at 1 bar and two temperatures, 25 and 0 °C, respectively.