New method turns carbon emissions into solid cement ingredients

Researchers at the University of Michigan, led by chemist Charles McCrory, have developed a novel method to capture carbon dioxide (CO₂) from the air and convert it into metal oxalates, stable solid compounds that can serve as precursors for cement production. This approach aims to transform CO₂, typically viewed as a waste product, into valuable building materials, potentially reducing the carbon footprint of construction. The work is part of efforts by the Center for Closing the Carbon Cycle (4C), funded by the U.S. Department of Energy, which focuses on converting captured carbon into useful fuels and industrial products. The team’s innovation centers on using trace amounts of lead as a catalyst to convert CO₂ into metal oxalates via electrochemical reactions. By employing specially designed polymers, they reduced the lead catalyst to parts per billion—levels comparable to natural impurities—addressing previous environmental and health concerns associated with higher lead usage. In the process, CO₂ is electrochemically transformed into oxalate ions, which then combine with metal ions released from an electrode to form solid metal oxalates. These solids are stable and do not revert to CO₂ under normal conditions, making them promising for cleaner cement production. While electrolysis of CO₂ is already being scaled up industrially, the researchers note that further work is needed to scale the metal oxalate production step, but they remain optimistic about its feasibility. This breakthrough offers a potential pathway to reduce the environmental impact of traditional Portland cement manufacturing, which is energy-intensive and a major source of global carbon emissions. By turning pollution into building blocks, the research opens new avenues for sustainable construction materials and carbon capture utilization. The study detailing these findings was published in the journal Advanced Energy.