Environmental Conservation

CO₂ Reduction in Exhaust Gases Breathes Life into Earth’s Climate

Electrochemical setup for CO2 reduction with nickel-copper catalyst

Adib Mahbub from the team at the Center for Electrochemistry is the first author of the paper. Image Credit: RUB, Marquard

To protect the climate, the aim is to recover CO₂ from combustion processes for use as valuable materials. This is challenging because exhaust gases contain not only CO₂ but also other gases. An international research team led by Prof. Dr. Wolfgang Schuhmann from the Zentrum für Elektrochemie at Ruhr-Universität Bochum has shown how CO₂ can be electrochemically reduced even at low concentrations in order to reuse it. They report on this in the journal “Angewandte Chemie” on December 23, 2024.

Unlike under many laboratory conditions, CO₂ makes up only a small portion of the gas mixture in exhaust gases or in the atmosphere. In order to extract it under realistic conditions and reuse it as a valuable material, catalytic processes must therefore work even when the CO₂ concentration is low.

Preventing competing reactions

“Our problem lies in the competing reactions that occur in a catalyst,” explains Wolfgang Schuhmann. “The fewer CO₂ molecules there are to convert, the more likely it becomes that hydrogen is produced instead of the desired product.” If you adjust the electrolyte and choose a more alkaline solution to prevent this, you face another problem: CO₂ is converted to carbonate and is no longer available for the desired reactions.

Successful catalytic processes for CO₂ reduction have already been described up to a CO₂ content of 10 to 20 percent. But what if the content is even lower? “By using a superactive nickel-copper-based catalyst, we were able to achieve successful catalysis with up to five percent CO₂ content,” says Adib Mahbub, the first author of the publication. Below that, the researchers had to resort to special measures: By adjusting the electrical potentials and the electrolyte, it was even possible to carry out a reduction from a gas mixture containing only two percent CO₂. “Although this does involve an energy loss, through smart process control it makes accessible sources that we previously could not use for CO₂ reduction,” says Wolfgang Schuhmann. “Future generations will have to build on such concepts if they want to remove CO₂ from the atmosphere, where the CO₂ content is even lower.”

Funding

This work was financially supported by the European Research Council (ERC) as part of the European Union’s Horizon 2020 research and innovation program (CasCat 833408).

Scientific contacts
Prof. Dr. Wolfgang Schuhmann
Analytical Chemistry – Center for Electrochemistry
Faculty of Chemistry and Biochemistry
Ruhr University Bochum
Phone Number: +49 234 32 26200
Email ID: wolfgang.schuhmann@ruhr-uni-bochum.de
Website of the working group: https://www.elan.ruhr-uni-bochum.de/elan/index.html

Original Publication
Muhammad Adib Abdillah MahbubDr. Debanjan DasDr. Xin WangDr. Guilong LuProf. Martin MuhlerProf. Wolfgang Schuhmann
Journal: Angewandte Chemie
Article Title: Towards the Use of Low-Concentration CO2 Sources by Direct Selective Electrocatalytic Reduction
Article Publication Date: 23 December 2024
DOI: https://doi.org/10.1002/anie.202419775

Media Contact
Meike Drießen
Head of Editorial Office
Phone Number:
+49 234 32 26952
Email ID:
meike.driessen@rub.de

Source: IDW

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