Recent Advances of Porous Solids for Ultradilute CO2 Capture

The urgency of dealing with global climate change caused by greenhouse gas(GHG) emissions is increasing as the carbon dioxide(CO2) concentration in the atmosphere has reached a record high value of 416 ppm(parts per million). Technologies that remove CO2 from the surrounding air(direct air capture, DAC) could result in negative carbon emissions, and thus attracts increasing attention. The steady technical progress in adsorption-based CO2 separation greatly advanced the DAC, which largely relies on advanced sorbent materials. This review focuses on the latest development of porous solids for air capture; first discussed the main types of sorbents for air capture, which include porous carbons, zeolites, silica materials, and metal-organic frameworks(MOFs), particularly their modified counterparts. Then, we evaluated their performances, including uptake and selectivity under dry and humid CO2 streams for practical DAC application. Finally, a brief outlook on remaining challenges and potential directions for future DAC development is given.