Sustainably produced artificial leaf creates renewable fuels on a cloudy day

22 Oct 2019

The new artificial leaf. Image: Virgil Andrei/PA

Scientists have found a way to sustainably create an artificial leaf that can produce clean gas, even when sunlight is limited.

Scientists have taken a leaf from nature’s book in an effort to make clean gas found in fuels, pharmaceuticals and plastics. An artificial leaf has been developed at the University of Cambridge which mimics photosynthesis, the process plants use to gather energy from sunlight, CO2 and water.

At present, a gas known as syngas is produced from fossil fuels, but the carbon-neutral solution made by scientists could eventually be used to develop a sustainable liquid fuel alternative to petrol. Prof Erwin Reisner and his team have managed to ensure the device does not release any additional CO2 into the atmosphere.

“You may not have heard of syngas itself, but every day you consume products that were created using it,” explained Reisner, from Cambridge’s Department of Chemistry, a senior author of the research.

“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.”

Scientists say they have managed to make the artificial leaf sustainable, unlike others in the past, because of the combination of materials and catalysts they used. The overall process is achieved using two light absorbers, similar to the molecules in plants that harvest sunlight, which are combined with a catalyst made from cobalt.

Scientist Virgil Andrei in a white lab coat holding an artificial leaf in a lab.

Virgil Andrei, one of the scientists working on an artificial leaf that can produce clean gas. Image: Chanon Pornrungrog/PA

Liquid fuel in one step

When in water, one light absorber uses the catalyst to produce oxygen, while the other carries out the chemical reaction that reduces CO2 and water into carbon monoxide and hydrogen, forming the syngas mixture. What’s more, the artificial leaf is able to work just as well on cloudy and overcast days.

“This means you are not limited to using this technology just in warm countries, or only operating the process during the summer months,” said Virgil Andrei, a PhD student and first author of the paper, published in the Nature Materials journal. “You could use it from dawn until dusk, anywhere in the world.

“We are aiming at sustainably creating products such as ethanol, which can readily be used as a fuel.

“It’s challenging to produce it in one step from sunlight using the CO2 reduction reaction. But we are confident that we are going in the right direction, and that we have the right catalysts, so we believe we will be able to produce a device that can demonstrate this process in the near future.”

Reisner continued: “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 CO2 and water.

“There is a major demand for liquid fuels to power heavy transport, shipping and aviation sustainably.”

– PA Media