Israeli Innovation: Electrochemical Production of Urea from Carbon Dioxide and Nitrates
Researchers at Ariel University have developed an innovative copper-sulfur catalyst that enables the efficient production of urea from carbon dioxide and nitrates under ambient conditions.
Urea is a substance known primarily for its widespread use as an agricultural fertilizer and as a raw material for the plastics industry. In biological systems, it is produced from the breakdown of proteins. Today, it is increasingly important in renewable energy technology, serving as a potential fuel source for fuel cells and electrolyzers.
The traditional industrial production of urea, based on the 19th-century Bosch-Meiser process, requires extreme conditions: pressures reaching 200 atmospheres and temperatures around 400 degrees Celsius. This industry consumes 1–3% of global annual energy and accounts for 1.4% of global carbon emissions. To foster a circular economy, scientists are seeking green electrocatalytic alternatives that utilize carbon dioxide and nitrates under moderate conditions.
Nitrates are preferred over gaseous nitrogen due to their higher water solubility and weaker chemical bonds (204 kJ/mol compared to 941 kJ/mol for nitrogen). Furthermore, nitrates are common industrial water pollutants. A major challenge in this electrochemical process is the competition for electrons from the parallel hydrogen evolution reaction.
PhD student Landy Darda and a research team led by Prof. Alex Schechter from the Department of Chemical Sciences at Ariel University presented an advanced solution in the Chemical Engineering Journal. They developed a Cu2S/CuS-based catalyst that efficiently directs the reaction toward C-N coupling while suppressing hydrogen production.
"We offer a sustainable path for producing green urea while addressing nitrate pollution and carbon dioxide emissions," explains Prof. Schechter. The high electronegativity of sulfur alters the electronic structure of the copper, creating active sites for carbon dioxide adsorption and nitrogen fixation. This catalyst serves as a cost-effective alternative to expensive noble metal-based catalysts.
Laboratory results were exceptional, with 80% of the electrical current directed toward urea production. Using isotope labeling, the researchers confirmed that the nitrogen in the final product originated directly from the raw materials. This development paves the way for decentralized, eco-friendly fertilizer production directly in the field.
