The ongoing emission of carbon dioxide into the atmosphere significantly contributes to global warming and climate change, leading to more frequent extreme weather situations. Researchers have now introduced an effective technique for transforming carbon dioxide into ethanol, which can serve as an eco-friendly raw material for various chemical uses.
The ongoing release of carbon dioxide into the atmosphere is a significant factor behind global warming and climate change, resulting in more extreme weather events. Researchers at Johannes Gutenberg University Mainz (JGU) have introduced a method for converting carbon dioxide into ethanol effectively, providing a sustainable raw material for chemical applications. “We can remove the greenhouse gas CO2 from the atmosphere and reintegrate it into a sustainable carbon cycle,” stated Professor Carsten Streb from the JGU Department of Chemistry. His research team demonstrated how carbon dioxide can be transformed into ethanol through electrocatalysis. If green electricity is utilized in this process, it could be sustainable – allowing food crops that are currently used for ethanol production to be redirected back to food supply. According to Carsten Streb, while this conversion approach has only been tested in the lab, it holds potential for large-scale implementation. The findings have been published in ACS Catalysis.
Effective tandem system enables selective electrocatalytic conversion
The electrochemical conversion of CO2 into multi-carbon products like ethanol represents an excellent method to produce high-energy fuels and valuable chemical raw materials. It also utilizes CO2 as a precursor, thus helping to reduce atmospheric levels of this gas. “We need appropriate catalysts that can facilitate this conversion with high selectivity, ensuring we obtain a good yield of our target product, which is ethanol,” explained Streb.
To achieve this, his research group developed a specialized electrode where the necessary chemical reactions occur. This electrode is coated with a black powder containing specific amounts of cobalt and copper, which must also be positioned correctly on the electrode. “The primary challenge is to initiate a reaction with carbon dioxide,” said Streb. “The bonds between the atoms in this molecule are quite strong, but cobalt can break them.” This reaction initially forms carbon monoxide, which is not suitable for the chemical industry. In a second stage, copper is introduced to convert this into ethanol. “This will only work effectively if cobalt and copper are placed closely on the electrode,” Streb noted, highlighting the technique that led to their successful outcome.
Future focus on improving selectivity
Currently, the selectivity of the process stands at 80%, meaning that 80% of the input material converts into ethanol, marking the highest achievement in research to date. Dr. Soressa Abera Chala played a crucial role in enhancing these results. He is the lead author of the research paper and joined the team as a postdoc with a Humboldt Research Fellowship from Ethiopia. Two co-authors, Dr. Rongji Liu and Dr. Ekemena Oseghe, are also working with Streb’s group as fellows of the Alexander von Humboldt Foundation. The team is now striving to boost the yield of this process to between 90% and 95%. Ideally, they aim for a catalyst that achieves 100% selectivity so that no byproducts other than ethanol remain at the conclusion of the process.
Collaborative efforts in the “CataLight” Research Center
Success hinges on effective process management and particularly on the electrode’s loading with cobalt and copper. “We aim to visualize individual atoms, which can be accomplished with a specialized type of electron microscope,” said Streb. To facilitate this, the Mainz chemists have partnered with colleagues at Ulm University as part of the Collaborative Research Center / Transregio “CataLight” (CRC/TRR 234). Their objective is to develop a catalyst that not only performs efficiently but also maintains its function for an extended duration. The system has demonstrated remarkable stability, retaining its performance even after several months.
The widespread availability of cobalt and copper is a significant consideration in selecting these metals. While it is possible to conduct the entire process using valuable metals like platinum or palladium, it would be at prohibitive costs with limited commercial viability.
Eco-friendly ethanol production conserves food resources and introduces a new energy source
“By utilizing readily available raw materials as catalysts, we are aligning with current research trends that increasingly prioritize non-precious metals,” stressed Professor Carsten Streb. This process could eventually facilitate sustainable ethanol production from green electricity and carbon dioxide emissions from power plants. Currently, a large volume of ethanol is produced from sugarcane and corn in Brazil, which renders these crops unavailable for local food needs. The method introduced here could pioneer a sustainable and innovative way to generate ethanol, which could be stored and utilized for decentralized power generation as needed.
