N-Doped Poly pyrrole-Based Porous Carbons for CO_2 Capture

摘要

Highly porous N-doped carbons have been successfully prepared by using KOH as activating agent and polypyrrole (PPy) as carbon precursor. These materials were investigated as sorbents for CO2 capture. The activation process was carried out under severe (KOH/PPy = 4) or mild (KOH/PPy = 2) activation conditions at different temperatures in the 600-800 C range. Mildly activated carbons have two important characteristics: i) they contain a large number of nitrogen functional groups (up to 10.1 wt% N) identified as pyri-donic-N with a small proportion of pyridinic-N groups, and ii) they exhibit, in relation to the carbons prepared with KOH/PPy = 4, narrower micropore sizes. The combination of both of these properties explains the large CO_2 adsorption capacities of mildly activated carbon. In particular, a very high CO_2 adsorption uptake of 6.2 mmol-g~(-1) (0 ℃) was achieved for porous carbons prepared with KOH/PPy = 2 and 600 ℃ (1700 m~2-g~(-1) pore size « 1 nm and 10.1 wt% N). Furthermore, we observed that these porous carbons exhibit high CO_2 adsorption rates, a good selectivity for CO_2-N_2 separation and it can be easily regenerated.