Role of nitrogen doping and pore volume for CO2 capture in metal-organic framework derived ultramicroporous carbon material

Abstract

We report the synthesis of four MOF-derived nitrogen and oxygen co-doped ultramicroporous/microporous carbon (MNOUCs) at different carbonization temperatures and their applications as adsorbents for efficient CO2 capture. MNOUC-900, carbonized at 900 ℃ having the highest surface area of 1320 m2/g and highest ultramicropore volume of 0.205 cm3 g−1 showed the maximum CO2 uptake of 4.65 mmol g−1 at 0 ℃ and 1 bar. Contrary to this, MNOUC-600, which was synthesized at 600 ℃ showed the highest CO2/N2 selectivity of 31. This study revealed that CO2 uptake had been found to be correlated with ultramicropore volume while selectivity (CO2 vs N2) improves with increasing basic nitrogen functionalities such as pyridinic and pyrollic. The heat of adsorption values was found to be 25–40 kJ mol−1 suggesting the physisorption nature of the interaction. Dynamic CO2 uptake experiment was performed for MNOUC-900, which revealed its good efficiency to be used as a CO2 adsorbent.