Importance of Micropore–Mesopore Interfaces in Carbon Dioxide Capture by Carbon‐Based Materials

Abstract

Mesoporous carbonaceous materials (Starbons®) derived from low-value/waste bio-resources separate CO2 from CO2 /N2 mixtures. Compared to Norit activated charcoal (AC), Starbons® have much lower microporosities (8-32 % versus 73 %) yet adsorb up to 65 % more CO2 . The presence of interconnected micropores and mesopores is responsible for the enhanced CO2 adsorption. The Starbons® also showed three-four times higher selectivity for CO2 adsorption rather than N2 adsorption compared to AC.

Prediction by Convolutional Neural Networks of CO2/N2 Selectivity in Porous Carbons from N2 Adsorption Isotherm at 77 K

“…[5b] Our finding points out a design strategy for porous carbons in terms of post-combustion carbon capture: creating a porous carbon with distinct micropores (< 2 nm) and mesopores (3-7 nm) that are well separated in the PSD. This conclusion echoes a few recent studies [5,13] in emphasizing the importance of mesopores in porous carbons for CO 2 uptake and gas separation. More important, we provide a target porosity to guide synthesis.…”

Solvent‐Free Self‐Assembly to the Synthesis of Nitrogen‐Doped Ordered Mesoporous Polymers for Highly Selective Capture and Conversion of CO2

“…The N1s spectra can be fitted and deconvoluted into three peaks. Besides the peak associated with amino nitrogen at 399.5 eV, two other peaks associated with pyridinic and pyrrolic nitrogen at 398.4 and 400.9 eV are also determined . The pyridinic and pyrrolic nitrogen should be produced from the pyrolysis of the phenolic resin network during the removal of the template at 350 °C.…”

“…To date, most of the reported nitrogen‐functionalized porous polymers for CO 2 capture are abundant in micropores, which results in a large barrier for gas diffusion in the inner pores and makes it hard for CO 2 to access the nitrogen functionality. Some recent works have begun to pay attention to the importance of mesopores in the selective capture of CO 2 . The highly ordered mesopores in synthesized N‐OMPs not only provide a pathway for the fast diffusion of gas in the inner pores but also make the nitrogen functionality more easily accessible to CO 2 .…”

Synthesis, characterisation and carbon dioxide capture capacities of hierarchically porous Starbons®

“…8 Established wisdom is that adsorption of gases occurs best on microporous solids with pore diameters less than 0.8 nm 26,27 Nevertheless, Starbons ® were found to physisorb up to 50% more carbon dioxide and to show 3-4 times better selectivity for carbon dioxide over nitrogen than microporous activated carbon. 28 They were subsequently shown to also adsorb ammonia, hydrogen sulphide and sulphur dioxide more effectively than microporous carbon. 29 The above applications all benefit from the favourable mass-transfer rates associated with highly mesoporous structures.…”