Sulfur Dioxide Capture in Metal-Organic Frameworks, Metal-Organic Cages, and Porous Organic Cages.

Capture, storage and subsequent controlled release or transformation of sulfur dioxide (SO 2 ) in mild conditions is still a challenge in the material science field. Recent advances in the use of porous materials have demonstrated good SO 2 capture, particularly in metal-organic frameworks (MOFs), metal-organic cages (MOCs), and porous organic cages (POCs). The striking feature of these porous materials is the high SO 2 uptake capacity in reversible settings. A partially fluorinated MIL-101(Cr) is stand-alone material with the highest SO 2 uptake in chemically stable MOFs. Likewise, metal-free adsorbents like POCs exhibits a reversible SO 2 uptake behavior. The SO 2 adsorption characteristics of these three structurally and functionally unique adsorbent systems are highly dependent on the binding sites and mode of binding of SO 2 molecules. This Review has highlighted the preferential binding sites in these materials to give a full perspective on the field. We anticipate that it will offer valuable information on the progress made towards improving SO 2 capture by hybrid systems.