Chemical engineers at the Massachusetts Institute of Technology have developed an efficient way to convert carbon dioxide to carbon monoxide using a DNA-bound catalytic process that can significantly reduce greenhouse gas emissions. This breakthrough provides a new route for producing valuable chemicals from CO2, with the potential for large-scale industrial applications. Credit: SciTechDaily.com
catalyst connected to DNA Increases the efficiency of the electrochemical conversion of CO2 to CO, a building block of many compounds.
Massachusetts Institute of Technology Chemical engineers have devised an efficient way to convert carbon dioxide into carbon monoxide. Carbon monoxide is a chemical precursor that can be used to produce useful compounds such as ethanol and other fuels.
Expanding this process for industrial use could remove carbon dioxide from power plants and other sources, reducing the amount of greenhouse gases released into the atmosphere.
Chemical engineers at MIT have shown that the conversion of carbon dioxide to carbon monoxide can be made more efficient by using DNA to link a catalyst (blue circle) to an electrode. Credit: Christine Daniloff, MIT. iStock
Innovative decarbonization technology
“This allows us to take carbon dioxide dissolved in exhaust gases and oceans and convert it into profitable chemicals. We can take in carbon dioxide, so it’s a real path to decarbonization.2This is a greenhouse gas and turns it into something useful for chemical manufacturing,” said Ariel Furst, Paul M. Cook Career Development Assistant Professor of Chemical Engineering and senior author of the study.
The new approach uses electricity to perform chemical transformations with the help of a catalyst tethered to an electrode surface by a DNA strand. This DNA acts like Velcro to keep all reaction components close together, making the reaction much more efficient than if all components were floating in solution.
Furst founded a company called Helix Carbon to further develop this technology.Gang Fan, a former MIT postdoc, is the lead author of the paper, which American Chemical Society Journal Au. Other authors include Nathan Corbin PhD '21, Minju Chung PhD '23, former MIT postdoc Thomas Gill and his Amruta Karbelkar, and Evan Moore ('23).
Decomposition of CO2
To convert carbon dioxide into a useful product, it must first be converted into carbon monoxide. One way to do this, he says, is to use electricity, but the amount of energy required for that type of electrocatalysis is prohibitively expensive.
To reduce these costs, researchers have attempted to use electrocatalysts that can speed up reactions and reduce the amount of energy that needs to be added to the system. Her one type of catalyst used for this reaction is a type of molecule known as a porphyrin. Porphyrins contain metals such as iron and cobalt and are similar in structure to heme molecules that carry oxygen in the blood.
In this type of electrochemical reaction, carbon dioxide is dissolved in water in an electrochemical device with electrodes that drive the reaction. The catalyst is also suspended in the solution. However, this setup is not very efficient. This is because the carbon dioxide and catalyst must come into contact at the electrode surface, which does not occur frequently.
To make reactions occur more frequently and increase the efficiency of electrochemical conversions, Furst began working on ways to attach catalysts to the surface of electrodes. For this application he seems DNA to be the ideal choice.
“DNA is relatively cheap and can be chemically modified to control the interactions between the two strands by changing its sequence,” she says. “It's like a sequence-specific Velcro that allows us to control interactions that are very strong but reversible.”
To attach a single strand of DNA to a carbon electrode, the researchers used two “chemical handles.” One was on the DNA and one was on the electrode. These handles can be snapped together to form a permanent bond. The complementary DNA sequence is then attached to the porphyrin catalyst, so that when the catalyst is added to the solution, it reversibly binds, like Velcro, to the DNA already bound to the electrode.
Once the system is set up, researchers apply an electrical potential (or bias) to the electrodes, and the catalyst uses this energy to convert carbon dioxide in solution to carbon monoxide. This reaction also produces a small amount of hydrogen gas from the water. After the catalyst wears out, heating the system allows him to release it from the surface and replace it with a new one by breaking the reversible bond between the two DNA strands.
Breakthrough electrochemical conversion
Using this approach, the researchers were able to increase the faradic efficiency of the reaction to 100%. This means that all the electrical energy input into the system goes directly into the chemical reaction without wasting any energy. If the catalyst is not bound by DNA, the faradaic efficiency is only about 40%.
Because the carbon electrodes the researchers used are much cheaper than traditional metal electrodes, Furst says the technology could be scaled up for industrial use fairly easily. Additionally, the catalyst is inexpensive as it does not contain any precious metals, and only a small concentration of catalyst is required on the electrode surface.
The researchers plan to try using this approach to make other products, such as methanol and ethanol, by swapping out different catalysts. Helix Carbon, the company founded by Furst, is also working to further develop the technology for possible commercial use.
Reference: “Highly Efficient Carbon Dioxide Electroreduction with DNA-Directed Catalyst Immobilization” Gang Fan, Nathan Corbin, Minju Chung, Thomas M. Gill, Evan B. Moore, Amruta A. Karbelkar and Ariel L. Furst, 2024.3 25th of the month, jacks o.
DOI: 10.1021/jacsau.3c00823
This research received funding from the U.S. Army Research Office, the CIFAR Azrieli Global Scholars Program, the MIT Energy Initiative, and the MIT Deshpande Center.
