Producing clean fuels that have a minimal carbon footprint is an arduous task as current techniques also create by-products in the process, making it difficult and expensive to filter them out.

That may no longer be the case soon thanks to a team of scientists from the University of Cambridge who have developed a renewable energy device that mimics photosynthesis to produce oxygen and formic acid from sunlight, carbon dioxide and water.

Inspired by the way plants create their own energy, the device is a slim sheet that converts sunlight, carbon dioxide and water into oxygen and formic acid, a storable fuel that can be used directly or be turned into hydrogen fuel.

Harnessing sunlight to convert carbon dioxide into fuel is a promising way to reduce carbon emissions and transition away from fossil fuels, but it is challenging to produce these clean fuels without unwanted by-products.

“It’s been difficult to achieve artificial photosynthesis with a high degree of selectivity so that you’re converting as much of the sunlight as possible into the fuel you want, rather than be left with a lot of waste,” explains Qian Wang from the university. “We were surprised how well it worked in terms of its selectivity – it produced almost no by-products.”

Less by-product makes separating the fuel easier and cheaper. The test device measured just 20 square centimeters in size, but the scientists said it would be simple and inexpensive to create a larger-scale version.

This “clean” energy has no carbon emissions, removes carbon dioxide from the atmosphere, and could reduce dependency on traditional fossil fuels.