UTMESA+MESA+ InstituteNewsNew insights in CO₂ conversion with electricity

New insights in CO₂ conversion with electricity Chemical environment around the electrode is key to producing formic acid efficiently

Researchers from the Department of Chemical Engineering, led by Georgios Katsoukis, have discovered how the chemical environment around copper electrodes can dramatically influence the conversion of carbon dioxide (CO₂) into formate. This discovery can help improve the selectivity in CO₂ reduction reactions, offering new insights into how to control these processes more effectively.

Key Discoveries
  1. Chemical Environment Dictates Efficiency: The researchers found that mildly acidic conditions near the copper electrode are essential for converting CO₂ into formate quickly.
  2. Bicarbonate’s Surprising Role: Contrary to previous assumptions, bicarbonate, a form of CO₂ in water, also contributes to formate production, though less efficiently than CO₂.
  3. Carbonate's Limitation: Carbonate does not contribute to formate production.
  4. Copper Carbonate Formation: The study also identified that under certain conditions, copper carbonate can form on the electrode surface, leading to its deactivation.

One of the ways to create a more sustainable and circular economy is to capture CO2 emissions and transform them into useful resources. But to do so, these CO2 reduction technologies need to be optimised and far more efficient. In this study, the research team investigated how CO₂ reacts at the surface of copper electrodes in an aqueous environment. By altering the pH near the electrode, they discovered that the local chemical environment is crucial in determining how quickly and efficiently CO₂ can be converted into formate, a useful chemical with many industrial applications.

Selectivity in CO₂ reduction reactions has been a longstanding challenge, as multiple products can form depending on the reaction conditions. This finding challenges the traditional focus on catalyst material alone and emphasises the importance of optimising the surrounding chemical conditions.

Major Implications

This research highlights the importance of controlling the chemical environment in CO2 reduction processes to improve selectivity and efficiency. By fine-tuning the condition around the copper electrode, it may be possible to enhance the selectivity towards desired products like formate. At the same time it could also extend the life of the electrode. These advancements could play a crucial role in developing more efficient carbon dioxide conversion systems.

The findings from this study provide a blueprint for future research and the development of CO₂ reduction technologies. By focusing on the optimisation of the chemical environment, in addition to the catalyst, scientists can work towards creating more selective and efficient systems. This approach brings us closer to practical solutions for transforming CO₂ emissions into useful resources, fostering a more sustainable and circular economy.

More information

Dr Georgios Katsoukis is assistant professor in the research group Photocatalytic Synthesis (PCS; Faculty of S&T / MESA+). Together with researchers Hilbert Heida, Merlin Gutgesell and Prof Dr Guido Mul, he published this work in a research article in the scientific journal ACS Catalysis. The article, entitled ‘Time-Resolved Infrared Spectroscopic Evidence for Interfacial pH-Dependent Kinetics of Formate Evolution on Cu Electrodes’, is open access and can be read online.

DOI: 10.1021/acscatal.4c03521

K.W. Wesselink - Schram MSc (Kees)
Science Communication Officer (available Mon-Fri)