Comparative study of activation methods to design nitrogen-doped ultra-microporous carbons as efficient contenders for CO2 capture

Microporous carbon materials are envisaged as efficient contenders for mitigating CO2 levels by virtue of their favorable surface chemistry, high specific surface area, tunable pore structures, moderate heat of adsorption, and facile regeneration. This study presents a solvent-free one-step polymerization and activation method for designing a series of nitrogen-enriched carbons to delineate the role played by nitrogen moieties and ultra-micropores on CO2 capture. Two activating agents were used at high temperature to fabricate microporous carbons with tunable pore structure and variable nitrogen content. The optimized material, MCKC-3, possesses high surface area (2060 m2/g) comprising of ultramicropores (<0.7 nm) and high nitrogen content (2.3 wt%). This material exhibit an outstanding CO2 uptake performance of 354 mg/g (8.03 mmol/g) at 273 K and 1 bar, comparable to the highest adsorption reported so far for carbon-based materials. In conclusion presence of both the ultra-micropores and nitrogen functionalities contribute a major role in CO2 adsorption, the former being predominant.