Energy

Real-world-ready artificial leaf can pluck carbon dioxide out of thin air

Real-world-ready artificial le...
Researchers have developed a new design of artificial leaf that's able to pull carbon dioxide out of the air
Researchers have developed a new design of artificial leaf that's able to pull carbon dioxide out of the air
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An illustration of the new artificial leaf design, showing how carbon dioxide (red and black balls) enter the leaf at the top as water evaporates out the bottom. Once inside, the artificial photosynthesis system (purple circle) converts the CO2 to CO
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An illustration of the new artificial leaf design, showing how carbon dioxide (red and black balls) enter the leaf at the top as water evaporates out the bottom. Once inside, the artificial photosynthesis system (purple circle) converts the CO2 to CO
Researchers have developed a new design of artificial leaf that's able to pull carbon dioxide out of the air
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Researchers have developed a new design of artificial leaf that's able to pull carbon dioxide out of the air

Plants are amazing little powerhouses, converting sunlight, water and carbon dioxide into energy. Over the last few years humans have tried to mimic this with artificial leaves, but they're never quite up to scratch. Now, researchers from the University of Illinois at Chicago have designed a new version that could work under real-world conditions, sucking carbon dioxide out of the air and creating oxygen and synthetic fuels.

One of the first artificial leaves came out of Harvard in 2011, using sunlight to split water into harvestable hydrogen and oxygen gas. Other versions since then have used similar technologies to create electricity, liquid fuels, fertilizer, and even drugs. Currently, the most promising artificial leaves do a decent job of absorbing carbon dioxide, but only under lab conditions.

"So far, all designs for artificial leaves that have been tested in the lab use carbon dioxide from pressurized tanks," says Meenesh Singh, corresponding author of the study. "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 flue gas, which is the gas given off by coal-burning power plants."

The UIC researchers say their new artificial leaf design is that kind of real-world ready. And it sounds surprisingly simple – it's basically a regular old artificial photosynthesis unit, wrapped in a new transparent capsule. This outer layer is a semi-permeable membrane made of quaternary ammonium resin, and it's filled with water.

An illustration of the new artificial leaf design, showing how carbon dioxide (red and black balls) enter the leaf at the top as water evaporates out the bottom. Once inside, the artificial photosynthesis system (purple circle) converts the CO2 to CO
An illustration of the new artificial leaf design, showing how carbon dioxide (red and black balls) enter the leaf at the top as water evaporates out the bottom. Once inside, the artificial photosynthesis system (purple circle) converts the CO2 to CO

The idea is that when the sun hits the device, the water slowly evaporates out through those pores. In its place, carbon dioxide is selectively sucked in from outside. In turn, that gas is converted into carbon monoxide by the artificial photosynthesis unit on the inside. From there, the carbon monoxide can be captured and used for a range of purposes, such as making synthetic fuels. Oxygen is a by-product as well, which can also be collected or just released back into the outside air, like a natural plant would do.

The researchers say their design would be up to 10 times more efficient at this process than a natural leaf. If enough of them are gathered in one place, that could produce a decent amount of fuel and do a good job of purifying the surrounding air.

The team calculated that in one day, 360 of these leaves – each measuring 170 cm long and 20 cm wide (67 x 7.9 in) – could be capable of producing half a ton of carbon monoxide, and pulling 10 percent of the carbon dioxide out of the air for about 100 m (328 ft) around the setup.

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

The research was published in the journal ACS Sustainable Chemistry & Engineering.

Source: University of Illinois at Chicago

8 comments
Alien
This sounds great ...but I'd like more information as to how the CO is extracted from the artificial leaf ...and perhaps even a picture of one of the 1.7m x 20cm strips. Also we need to know how cost-effective would this process be? Perhaps your contributor could dig just a little deeper?
Cryptonoetic
Approximately 50 billion leaves (~17 billion square meters) would be sufficient to sequester the ~110 million tons (per day) of human generated atmospheric CO2. If one leaf cost a buck, this would be a deal.
Jasbee_Jones
Or, we could just grow plants.
michael_dowling
Jasbee_Jones: Better to do both,real plants and these newfangled leaves.
noteugene
I like this concept more than polluting the seas, lakes and mountains with energy producing equiptment.
rude.dawg
This is great news. Congrats! But so let's say mankind does become successful in sucking out most of the carbon dioxide from of the atmosphere. What then? How much exactly will this stop or slow down the planet's 4.5 billion yr old climate from changing? I only ask because Australia' Chief Scientist Alan Finkel is on the record as saying that it's better for us to do something about carbon emissions, even if straight before he said that the impact would be virtually nothing.
Robert in Vancouver
We are pretty much in balance regarding the amount of CO2 there is compared to the amount needed to keep trees and foor crops alive and thriving. If we reduce CO2 we risk a world wide famine due to the slower growth and dying off of food crops. Food crops and all other flora need a lot of CO2 to grow and re-produce. That's why greenhouses pump CO2 in, it's to help their crops grow and produce food. The manic obsession about reducing CO2 is going to create a serious and deadly problem.
paul314
17 billion square meters is about is about 130,000 meters on a side, or 130 km. So basically the size of a large metropolitan area. Maybe you could interleave these things with solar roofs.