Exceptionally High CO₂ Adsorption at 273 K by Microporous Carbons from Phenolic Aerogels: The Role of Heteroatoms in Comparison with Carbons from Polybenzoxazine and Other Organic Aerogels

Author

Hojat Majedi Far
Parwani M. Rewatkar
Suraj Donthula
Tahereh Taghvaee
Adnan Malik Saeed
Chariklia Sotiriou-Leventis, Missouri University of Science and TechnologyFollow
Nicholas Leventis, Missouri University of Science and TechnologyFollow

Abstract

Phenolic aerogels containing oxygen and other polymeric aerogels containing both oxygen and nitrogen (polybenzoxazine and a polyamide-polyimide-polyurea co-polymer) are converted to carbon aerogels (800 °C/Ar), and are etched with CO₂ (1000 °C). Etching opens closed pores and increases micropore volumes and size. Heteroatoms are retained in the etched samples. All carbon aerogels are evaluated as CO₂ absorbers in terms of their capacity and selectivity toward CH₄, H₂, and N₂. CO₂ adsorption capacity is linked to microporosity. In most cases, monolayer coverage of micropore walls is enough to explain CO₂ uptake quantitatively. The interaction of CO₂ with micropore walls is evaluated via isosteric heats of adsorption, and is stronger with carbons containing only oxygen heteroatoms. The adsorption capacity of those carbons (5-6 mmol g^-1) is on par with the best carbon and polymeric CO₂ adsorbers known in the literature, with one exception however: etched carbon aerogels from low-density resorcinol-formaldehyde aerogels show a very high CO₂ uptake (14.8 ± 3.9 mmol g^-1 at ₂73 K, 1 bar) attributed to a pore-filling process that proceeds beyond monolayer coverage, whereas surface phenoxides engage in a thermally neutral carbonate forming reaction (surface-Oˉ + CO₂→ surface-O-(CO)-Oˉ) that continues until micropores are filled.

Recommended Citation

H. Majedi Far et al., "Exceptionally High CO₂ Adsorption at 273 K by Microporous Carbons from Phenolic Aerogels: The Role of Heteroatoms in Comparison with Carbons from Polybenzoxazine and Other Organic Aerogels," Macromolecular Chemistry and Physics, vol. 220, no. 1, Wiley-VCH Verlag, Jan 2019.

The definitive version is available at https://doi.org/10.1002/macp.201800333

Department(s)

Chemistry

Comments

The authors thank the Army Research Office for financial support under Award Number W911NF-14-1-0369.

Keywords and Phrases

CO2 uptake; isosteric heats of adsorption; phenolic aerogels; polybenzoxazine aerogels; selectivity

International Standard Serial Number (ISSN)

1022-1352; 1521-3935

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2019 Wiley-VCH Verlag, All rights reserved.

Publication Date

01 Jan 2019