Scientists at the UK's University of Cambridge have developed a renewable energy device that mimics photosynthesis by making fuel from sunlight, carbon dioxide and water.
Taking inspiration from the way that plants create their own energy, the device is a slim sheet that produces oxygen and formic acid from water, carbon dioxide and sunlight.
Formic acid can be stored and used as fuel on its own, or turned into hydrogen fuel.
Scientists have created a sheet that can be added to water and carbon dioxide and then exposed to sunlight to create formic acid
The device is made of photocatalysts ? materials that absorb light to create a reaction ? based on cobalt embedded on a sheet made of semiconductor powders. It doesn't require wires or electricity. When the sheet is submerged in a bath of water and carbon dioxide and then exposed to sunlight, a chemical reaction takes place.
Similar to photosynthesis, the absorption of the sunlight excites electrons into a higher state ? converting sunlight into potential chemical energy. With the sheet device, this energy is transferred when the electrons join the carbon dioxide and protons in the water to make a colourless yet pungent liquid called formic acid.
Formic acid occurs in nature in ants and bees, who produce it in their venoms and stings.  It's much easier to transport as a fuel source than hydrogen, as the latter requires low temperatures and high pressure to be moved safely.
"We want to get to the point where we can clean...