Ann Arbor Times

University of Michigan researchers, in collaboration with teams from the University of California, Davis and Los Angeles, have developed a method to convert carbon dioxide into metal oxalates. These compounds can serve as precursors for cement production, offering a new approach to utilizing industrial waste.

Charles McCrory, an associate professor at the University of Michigan, explained the significance of this research: “This research shows how we can take carbon dioxide, which everyone knows is a waste product that is of little-to-zero value, and upcycle it into something that’s valuable.” The project was inspired by McCrory's involvement with the Center for Closing the Carbon Cycle (4C), funded by the U.S. Department of Energy.

Portland cement production traditionally relies on limestone and calcium silicates but comes with high energy costs and a significant carbon footprint. The research team explored alternative methods using metal oxalates as potential substitutes. While lead has been identified as an effective catalyst for converting carbon dioxide into these oxalates, its use poses environmental and health risks due to required quantities.

The 4C team managed to reduce lead usage to trace levels through polymer control around catalyst sites. This innovation significantly decreases lead requirements while maintaining process efficiency. McCrory emphasized their approach: “By controlling the microenvironment surrounding the lead catalyst in the chemical reaction that converts carbon dioxide to oxalate, they can vastly reduce the amount of lead needed for the process.”

Jesús Velázquez from UC Davis co-led this study and contributed insights into using minimal lead amounts effectively: “Metal oxalates represent an underexplored frontier—serving as alternative cementitious materials, synthesis precursors and even carbon dioxide storage solutions,” he noted.

Anastassia Alexandrova from UCLA also co-led this study. Her team confirmed through calculations that trace impurities could function as catalysts: “In this work, we have an example of a trace lead impurity actually being a catalyst," she said.

The conversion process involves electrodes where one transforms carbon dioxide into dissolved oxalate ions while another releases metal ions that combine with these ions to form solid metal oxalates. According to McCrory: “Once converted into metal oxalate solid...it won’t be rereleased into atmosphere.”

Scaling up remains a challenge but researchers are optimistic about its feasibility despite hurdles like reducing large-scale reliance on hazardous materials such as lead.

“We are a ways away," said McCrory regarding scalability efforts; however he believes "it’s a scalable process."