Potential photo-switching sorbents for CO2 capture – A review

Porous materials with photochromic units are currently under investigation as light allows for environmentally friendly and highly energy-efficient control for gas separation and storage, chemical sensing, and drug delivery. In the application of photo-switching materials to CO2 capture, researchers have tried to endow a diversity of porous materials such as metal-organic frameworks and porous organic polymers with photo-responsive units. This review highlights photochromic units and methods used for different types of photo-responsive adsorbents of CO2 and some examples of adsorbents with photo-switching properties. These sorbents are also promising for application to direct air capture of CO2. In particular, the cost of adsorbent regeneration could be reduced by using sorbents with light-induced regeneration. The key purpose of this review is to motivate more research into photo-switching sorbents for CO2 capture with the control of capture or release by simply switching the light on and off.