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.