Over the past decades, scientists have worked to reduce excess atmospheric carbon dioxide (CO 2) emissions. One promising method captures atmospheric carbon dioxide (CO 2) and converts it through CO2 electrolysis into valuable chemicals and intermediates, such as ethanol and ethylene. Although significant research has been done to improve the selectivity and rate of CO2 electrolysis, it has not been possible to reduce the energy consumed by this high-power process.Researchers from the University of Illinois Urbana-Champaign have reported in ACS Energy Letters that they found a new way to use magnetism for CO2 electrolysis. This could reduce the amount of energy needed by the flow electrolyzer up to 60%.A typical CO2 flow electrolyzer uses electricity to power the reactions at the anode and cathodes. This is where carbon dioxide is reduced into useful products, and the anode is where water is oxidized.The majority of studies have been focused on increasing the efficiency at the cathode in reducing CO2 electrolysis at higher rates. However, this reaction requires less energy than the oxidation reaction at the anode, which often consumes more than 80% of the energy needed for CO2 electrolysis. There is therefore much room for improvement."The solution was right in front of us--of course the trick is to decrease the energy consumption at anode," stated Saket S. Bhargava (a graduate student in chemical- and biomolecular engineers at Illinois). "We decided to use a magnetic field at an oxygen evolving electrode to see what the effect on the whole system is if oxygen evolution was the problem."To achieve energy savings of 7% to 64%, they used a magnetic field at anode to increase mass transport to/from electrode. They also replaced the traditional iridium-precious metal catalyst with a nickel-iron catalyst made up of abundant elements.Paul Kenis, a professor of chemical and biomolecular and department head at Illinois, stated that "our ultimate goal is to convert carbon dioxide back into carbon based chemicals." "With this study we have shown how to further reduce the energy required for CO2 electrolysis. This will hopefully make this process more feasible for industry."###This research was supported by student fellowships from Shell, 3M and the Link Foundation. Other co-authors include University of Illinois students Daniel Azmoodeh and Xinyi Chen as well as Emiliana R. Cole, Anne Marie Esposito and Sumit Verma. Andrew A. Gewirth is a professor of chemistry.
