Wednesday, February 9, 2022

University of Delaware Engineers Attack CO2 Pollution


Three fuel cell experts discuss their project. From left to right, Yushan Yan, Brian P. Setzler, and Shimshon Gottesfeld. (Photo: Evan Krape)

The University of Delaware engineers captured 99% of carbon dioxide in the air when using their novel hydrogen-powered electrochemical system. The UD engineers have developed a fuel cell technology that uses cheaper catalysts and structural components, but these hydroxide exchange membrane fuel cells (HEMFCs) have a limitation. They cannot use direct supply of ambient air, because the carbon dioxide in the air reduces their performance.

The alkaline environment of hydroxide exchange membrane fuel cells potentially allows use of cost-effective catalysts and bipolar plates in devices. However, HEMFC performance is adversely affected by CO2 present in the ambient air feed. Here, we demonstrate an electrochemically driven CO2 separator (EDCS) to remove CO2 from the air feed using a shorted membrane that conducts both anions and electrons. This EDCS is powered by hydrogen like a fuel cell but needs no electrical wires, bipolar plates or current collectors, and thus can be modularized like a typical separation membrane.

The University of Delaware team has been attempting to improve fuel cell technology for over fifteen years. They realized that the sensitivity of the fuel cell to carbon dioxide, while detrimental to its efficiency in converting the chemical energy in fuel to electricity, meant it could be used as an effective tool for capturing carbon dioxide from the atmosphere.

An early prototype they developed using this approach, about the size of a 12-ounce (355 mL) soda can, could filter 10 liters of air per minute while scrubbing out >98% of the carbon dioxide present.

Brian Setzler, assistant research professor in chemical and biomolecular engineering and paper co-author explains, "Once we dug into the mechanism, we realized the fuel cells were capturing just about every bit of carbon dioxide that came into them, and they were really good at separating it to the other side," said

"It turns out our approach is very effective. We can capture 99% of the carbon dioxide out of the air in one pass if we have the right design and right configuration," said Professor Yushan Yan, Henry Belin du Pont Chair of Chemical and Biomolecular Engineering at the University of Delaware.

“This carbon dioxide problem has been with us for long enough, and we decided to turn the problem on its head and make it into a solution,” said Yan.

Read more here and here.  

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