Scientists have developed an “artificial leaf” that can suck up sunlight, carbon dioxide, and water, and puffs out syngas, a cocktail of gases that could one day be used as an alternative to fossil fuel gas.

While much more work is needed before these things are powering your house, the project marks a novel and inventive step towards sustainable energy sources. 

Chemists at the University of Cambridge wanted to develop a device that was inspired by photosynthesis, the natural process plants use to turn carbon dioxide into food with the help of sunlight energy. After seven years of hard work, the team has now presented their “artificial leaf” in the journal Nature Materials this week.

Just like a real leaf, it doesn’t require bright beaming sunlight to function. According to the researchers, it continues to work efficiently on rainy and overcast days too. This means the technology isn't limited to summer months or sunny countries to the same extent as conventional solar panels.

"You could use it from dawn until dusk, anywhere in the world," Virgil Andrei, PhD student and first author of the study, said in a statement.

The ”artificial leaf” uses carbon nanotubes with two light absorbers, similar to the molecules in plants that harvest sunlight, that are combined with a catalyst made from cobalt. Once immersed in water, the reaction begins, with one light absorber using the catalyst to produce oxygen, while the other carries out a chemical reaction to reduce carbon dioxide and water into carbon monoxide and hydrogen. 

These three gases are the foundation of syngas, an abbreviation for synthesis gas, made up of carbon monoxide, carbon dioxide, and hydrogen. Syngas has around half of the energy density of natural, so it's not as efficient to combust. However, it does hold several uses in manufacturing and in the production of liquid fuels. It also has the advantage of being considered a renewable energy source.

“You may not have heard of syngas itself but every day, you consume products that were created using it. Being able to produce it sustainably would be a critical step in closing the global carbon cycle and establishing a sustainable chemical and fuel industry,” added senior author Professor Erwin Reisner from Cambridge’s Department of Chemistry

“What we’d like to do next, instead of first making syngas and then converting it into liquid fuel, is to make the liquid fuel in one step from carbon dioxide and water,” added Reisner.