NOTT-202 is a "metal-organic framework" that works like a sponge, absorbing a number of gases at high pressures.
But as the pressure is reduced, CO2 is retained as other gases are released.
The development, reported in Nature Materials, holds promise for carbon capture and storage, or even for removing CO2 from the exhaust gases of power plants and factories.
Metal-organic frameworks have been considered promising structures to trap gases for a number of years. They are so named because they comprise atoms of a metallic element at their core, surrounded by scaffolds of longer, carbon-containing chains.
These complex molecules can be made to join together in frameworks that leave gaps suitable for capturing gases.
However, until now, such frameworks have been good primarily at gathering any gas passing through them; those that were selective for CO2 have proven to have a low capacity for storing the gas.