Solvent-free, one-pot synthesis of nitrogen-tailored alkali-activated microporous carbons with an efficient CO2 adsorption

초록

In the present study, a series of alkali-activated carbon materials (TOKs) were prepared by a single-pot polymerization-carbonization-activation method using KOH as a dynamic molecular porogen. The fabricated materials possess tunable porous network with high specific surface area (up to 2847 m(2)/g), large micropore volume (1.369 cm(3)/g), and high population of micropores in sub-nanometer range. At 1 bar and 273 K, activated carbons TOK-80 0 and TOK-90 0 adsorbed 6.57 mmol/g of CO2 and 6.85 mmol/g of CO2, attributed to well-defined micropores similar to 0.73 nm with large micropore volume. At low pressure (<0.2 bar), the adsorption capacity similar to 2.81 mmol/g of CO2 and isosteric heat of adsorption similar to 37.8 kJ/mol is maximum for the material possessing highest basic nitrogen-content (TOK-70 0), thereby suggesting a crucial role of basic nitrogen-groups in anchoring acidic CO2 molecules. Moreover, present work demonstrates an insight mechanism for CO2 adsorption by micropore filling and illustrate the high adsorption potential of micropores with the pore size less than 0.73 nm. Consequently, as-prepared activated carbons are proclaimed as efficient contenders for CO2 adsorption, an effort devoted for a green sustainable environment. (C) 2020 Elsevier Ltd. All rights reserved.

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