Anthropogenic carbon dioxide emissions are thought to be one cause of global warming. Current methods for CO₂ capture result in large energy penalties. Solid adsorbents are a potential method to capture CO₂, but the sorbent-sorbate affinity is critical in determining the energetic viability of such processes. In this study, the adsorption of CO₂ in a range of microporous organic polymers was tested. These materials adsorb up to 2.20 mmol/g CO₂ at 298 K and 1 bar, and thus performance is compared with related porous solids in the literature. The relationship between CO₂ uptake and apparent surface area and pore size is described, and this showed that heats of adsorption were important in the low pressure regime. The chemical tuning of gas-sorbent affinity provides a blueprint for the development of improved materials in this area.

We report here the carbon dioxide sorption properties for a series of conjugated microporous polymer (CMP) networks. These CMP materials incorporate a range of chemical functionalities including carboxylic acids, amines, hydroxyl groups, and methyl groups. The carboxylic acid functionalised network, rather than its amine analogue, shows the highest isosteric heat of sorption for CO₂. This supports recent computational predictions for metal–organic frameworks and suggests that acid-functionalised frameworks could outperform more widely studied amine sorbents in CO₂ capture and separation application.

Recent trends and challenges for the emerging materials class of microporous polymers are reviewed. See the main article for graphical abstract image credits.