Turning sunlight, carbon dioxide and water into fuel

Researchers at the University of Cambridge, UK, developed a device that converts sunlight, carbon dioxide and water into a carbon-neutral fuel, without the need for electricity.

The process mimics photosynthesis, the ability of plants to turn sunlight and carbon into energy and oxygen. The device uses the artificial photosynthesis to create oxygen and formic acid, a storable fuel that can be used directly or can be converted into hydrogen.

In January, we reported on a project by a team from the same university that developed an artificial leaf that produces syngas, a gas that is often produced from fossil fuels. The new process is similar, but works in a different way to produce formic acid.

The artificial leaf also requires components from solar cells, while the new device relies solely on photocatalysts embedded in a sheet to produce a so-called photocatalyst sheet. The cobalt-based sheets are made up of semiconductor powders, which can be prepared in large quantities easily and cost-effectively.

In addition, this new technology is more robust and produces clean fuel that is easier to store and shows potential for producing fuel products at scale. The test unit is 20 square centimetres in size, but the researchers say that it should be relatively straightforward to scale it up to several square metres. In addition, the formic acid can be accumulated in solution, and be chemically converted into different types of fuel.

Image: University of Cambridge