Direct air capture of CO2: from insights into the current and emerging approaches to future opportunities

Abstract

The rapid development of direct air capture (DAC) technologies has become critical in order to remove CO2 from the atmosphere and limit global warming to a maximum of 1.5°C. In this perspective, we provide a mini review of the current research on the emerging liquid- and solid-based sorbent materials to capture CO2, summarize the existing challenges of DAC technologies, and suggest future research directions to accelerate the development of DAC systems. In particular, the desired properties for a breakthrough sorbent that efficiently captures CO2 from the air and releases it for sequestration are described.

Understanding the Electrode–Electrolyte Interfaces of Ionic Liquids and Deep Eutectic Solvents

“…Electrocatalysis is yet another domain where the interfacial structure is crucial to understand such as the case for the electrochemical CO 2 reduction reaction (CO 2 RR) . In particular, ILs and DESs are known for their high CO 2 solubility − and thus present advantages compared to the aqueous electrolytes with low CO 2 solubilities . The [EMIM]­[BF 4 ] IL was even reported to co-catalyze the CO 2 RR .…”

Minimal Kinetic Model of Direct Air Capture of CO2 by Supported Amine Sorbents in Dry and Humid Conditions

“…Direct air capture (DAC) of CO 2 is an important solution to control CO 2 concentration in the atmosphere in order to mitigate climate change due to the increasing CO 2 level. − The DAC process usually involves the use of liquid or solid sorbents to selectively capture CO 2 from the air via chemisorption, followed by sorbent regeneration via a temperate/pressure swing to release concentrated CO 2 for storage or utilization. Supported amine sorbents have attracted significant attention for DAC, owing to their high adsorption capacity, excellent selectivity, beneficial coadsorption with moisture, and relatively mild energy requirements for sorbent regeneration. − Physically impregnated or chemically grafted amine groups onto porous supports such as mesoporous silica, alumina, carbon, and metal–organic frameworks have been reported. − The capture capacity is dictated by the reaction stoichiometry of amine groups with CO 2 in dry or humid conditions, the temperature, and the loading of amines in the porous supports. ,− …”

Composition–property relationships of choline based eutectic solvents: impact of the hydrogen bond donor and CO2 saturation

“…[6][7][8][9] In particular, by functionalizing the eutectic solvent components with CO 2 reactive moieties, CO 2 selectivity and absorption capacity have been shown to improve. [10][11][12] When functionalizing eutectic solvents for a target application, consideration of the interplay between the physical, chemical, thermal, and electrochemical properties is important as these properties vary with molecular structure and composition. [13][14][15][16] Therefore, understanding the structure-composition-property relationship is essential in the design of eutectic solvents for targeted applications.…”