Metal Cages Change SO2 Fate with Different Counterions

Like a factory with two functions, some metal-organic cages (MOCs) can either store the pollutant SO2 or turn it into a less harmful form. The key? Different chemical companions, known as counterions. By swapping these companions, scientists can flip the switch between just trapping SO2 or converting it into sulfate. Take Pd6L8 MOCs for instance, which can hold up to 3. 6 millimoles of SO2 per gram and prefer it over CO2 when nitrate isn’t around. But when nitrate is present, Pd6L8 can suck up 6 millimoles of SO2 per gram and turn it into sulfate with a high success rate at room temperature. This remarkable ability works regardless of humidity and can be recycled completely. This discovery could lead to new ways to deal with harmful gases using not just MOCs, but also other structured materials like MOFs, COFs, and POCs.