Moving artificial leaves out of the lab and into the air

February 12, 2019, University of Illinois at Chicago
An artificial, bio-inspired leaf. Carbon dioxide (red and black balls) enter the leaf as water (white and red balls) evaporates from the bottom of the leaf. An artificial photosystem (purple circle at the center of the leaf) made of a light absorber coated with catalysts converts carbon dioxide to carbon monoxide and converts water to oxygen (shown as double red balls) using sunlight. Credit: Meenesh Singh

Artificial leaves mimic photosynthesis—the process whereby plants use water and carbon dioxide from the air to produce carbohydrates using energy from the sun. But even state-of-the-art artificial leaves, which hold promise in reducing carbon dioxide from the atmosphere, only work in the laboratory because they use pure, pressurized carbon dioxide from tanks.

But now, researchers from the University of Illinois at Chicago have proposed a design solution that could bring artificial leaves out of the lab and into the environment. Their improved , which would use —a —from the air, would be at least 10 times more efficient than natural leaves at converting carbon dioxide to fuel. Their findings are reported in the journal ACS Sustainable Chemistry & Engineering.

"So far, all designs for artificial leaves that have been tested in the lab use carbon dioxide from pressurized tanks. In order to implement successfully in the real world, these devices need to be able to draw carbon dioxide from much more dilute sources, such as air and , which is the gas given off by coal-burning power plants," said Meenesh Singh, assistant professor of chemical engineering in the UIC College of Engineering and corresponding author on the paper.

Unhooking the pressurized carbon dioxide supply from these leaves means that they must have a way to collect and concentrate carbon dioxide from the air to drive their artificial photosynthetic reactions.

Singh and his colleague Aditya Prajapati, a in his lab, proposed solving this problem by encapsulating a traditional artificial leaf inside a transparent capsule made of a semi-permeable membrane of quaternary ammonium resin and filled with water. The membrane allows water from inside to evaporate out when warmed by sunlight. As water passes out through the membrane, it selectively pulls in carbon dioxide from the air. The artificial photosynthetic unit inside the capsule is made up of a light absorber coated with catalysts that convert the carbon dioxide to carbon monoxide, which can be siphoned off and used as a basis for the creation of various synthetic fuels. Oxygen is also produced and can either be collected or released into the surrounding environment.

"By enveloping traditional artificial leaf technology inside this specialized membrane, the whole unit is able to function outside, like a natural leaf," Singh said.

According to their calculations, 360 leaves, each 1.7 meters long and 0.2 meters wide, would produce close to a half-ton of carbon monoxide per day that could be used as the basis for synthetic fuels. Three hundred and sixty of these artificial leaves covering a 500-meter square area would be able to reduce dioxide levels by 10 percent in the surrounding air within 100 meters of the array in one day.

"Our conceptual design uses readily available materials and technology, that when combined can produce an artificial leaf that is ready to be deployed outside the lab where it can play a significant role in reducing greenhouse gases in the atmosphere," Singh said.

Explore further: Converting carbon dioxide to carbon monoxide using water, electricity

More information: Aditya Prajapati et al, Assessment of Artificial Photosynthetic Systems for Integrated Carbon Capture and Conversion, ACS Sustainable Chemistry & Engineering (2019). DOI: 10.1021/acssuschemeng.8b04969

Related Stories

Image: Jamming with the 'spiders' from Mars

July 16, 2018

This image from NASA's Mars Reconnaissance Orbiter, acquired May 13, 2018 during winter at the South Pole of Mars, shows a carbon dioxide ice cap covering the region and as the sun returns in the spring, "spiders" begin to ...

Recommended for you

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

Where is the universe hiding its missing mass?

February 15, 2019

Astronomers have spent decades looking for something that sounds like it would be hard to miss: about a third of the "normal" matter in the Universe. New results from NASA's Chandra X-ray Observatory may have helped them ...

What rising seas mean for local economies

February 15, 2019

Impacts from climate change are not always easy to see. But for many local businesses in coastal communities across the United States, the evidence is right outside their doors—or in their parking lots.

The friendly extortioner takes it all

February 15, 2019

Cooperating with other people makes many things easier. However, competition is also a characteristic aspect of our society. In their struggle for contracts and positions, people have to be more successful than their competitors ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

betterexists
not rated yet Feb 12, 2019
Carry and Drop those Leaves on Moon, before something unwanted reversion happens !
2 trips Every Fortnight !

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.