Sunlight-powered System Mimics Plants to Power Carbon Capture

Current methods of capturing and releasing carbon are expensive and so energy-intensive they often require, counterproductively, the use of fossil fuels. Taking inspiration from plants, Cornell University researchers have assembled a chemical process that can power carbon capture with an energy source that's abundant, clean and free: sunlight.

The research could vastly improve current methods of carbon capture—an essential strategy in the fight against global warming—by lowering costs and net emissions.

In the study, researchers found that they can separate carbon dioxide from industrial sources by mimicking the mechanisms plants use to store carbon, using sunlight to make a stable enol molecule reactive enough to "grab" the carbon.

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They also used sunlight to drive an additional reaction that can then release the carbon dioxide for storage or reuse.

It's the first light-powered separation system for both carbon capture and release.

Graduate student Bayu Ahmad is first author.

Phillip Milner, associate professor of chemistry and chemical biology in the College of Arts and Sciences
From a chemistry standpoint, this is totally different than what anybody else is doing in carbon capture. The whole mechanism was Bayu's idea, and when he originally showed it to me, I thought it would never work. It totally works.

The researchers tested the system using flue samples from Cornell's Combined Heat and Power Building, an on-campus power plant that burns natural gas, and found it was successful in isolating carbon dioxide.

Milner said this step was significant, as many promising methods for carbon capture in the lab fail when up against real-world samples with trace contaminants.

We'd really like to get to the point where we can remove carbon dioxide from air, because I think that's the most practical. You can imagine going into the desert, you put up these panels that are sucking carbon dioxide out of the air and turning it into pure high-pressure carbon dioxide. We could then put it in a pipeline or convert it into something on-site.

Milner's lab is also exploring how the light-powered system could be applied to other gasses, as separation drives 15% of global energy use.

There's a lot of opportunity to reduce energy consumption by using light to drive these separations instead of electricity.

The study was supported by the National Science Foundation, the U.S. Department of Energy, the Carbontech Development Initiative and Cornell Atkinson.