Sorbents for the Direct Capture of CO2 from Ambient Air

The urgency to address global climate change induced by greenhouse gas emissions is increasing. In particular, the rise in atmospheric CO2 levels is generating alarm. Technologies to remove CO2 from ambient air, or “direct air capture” (DAC), have recently demonstrated that they can contribute to “negative carbon emission.” Recent advances in surface chemistry and material synthesis have resulted in new generations of CO2 sorbents, which may drive the future of DAC and its large‐scale deployment. This Review describes major types of sorbents designed to capture CO2 from ambient air and they are categorized by the sorption mechanism: physisorption, chemisorption, and moisture‐swing sorption. Clearing the air: Pulling CO2 out of ambient air requires sorbents with unusual properties. Recent progress in surface chemistry and material synthesis have resulted in a new generation of solid CO2 sorbents tuned to the exacting demands of direct air capture and negative emissions on a global scale.