Molecular Trap Locks Away CO2

For the first time, researchers have obtained images of individual carbon dioxide molecules trapped in a series of molecular “cages”—and they borrowed an imaging technique from biologists to do it. Metal-organic frameworks (MOFs) are exceptionally porous polymers designed to capture particular gas molecules, letting scientists separate or purify various vapors. Even small amounts can slurp up a lot of gas: a single gram can have a gas-grabbing surface area nearly the size of two football fields. MOFs have been proposed for holding hydrogen in automobile tanks or fuel cells (without the need for extra cooling) and for grabbing and storing planet-warming carbon dioxide emissions, among many other uses.