For decades, scientists have searched for effective ways to remove excess carbon dioxide emissions from the air, and recycle them into products such as renewable fuels. But the process of converting carbon dioxide into useful chemicals is tedious, expensive, and wasteful and thus not economically or environmentally viable.

Now a discovery by researchers at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and Joint Center for Artificial Photosynthesis (JCAP) shows that recycling carbon dioxide into valuable chemicals and fuels can be economical and efficient — all through a single copper catalyst.

The work appears in the Dec. 17 edition of the journal Nature Catalysis.

Going where the action is: product-specific active sites

When you take a piece of copper metal, it may feel smooth to the touch, but at the microscopic level, the surface is actually bumpy — and these bumps are what scientists call “active sites,” said Joel Ager, a researcher at JCAP who led the study. Ager is a staff scientist in Berkeley Lab’s Materials Sciences Division and an adjunct professor in the Department of Materials Science and Engineering at UC Berkeley.

These active sites are where the magic of electrocatalysis takes place: electrons from the copper surface interact with carbon dioxide and water in a sequence of steps that transforms them into products like ethanol fuel; ethylene, the precursor to plastic bags; and propanol, an alcohol commonly used in the pharmaceutical industry.

Ever since the 1980s, when copper’s talent for converting carbon into various useful products was discovered, it was always assumed that its active sites weren’t product-specific — in other words, you could use copper as a catalyst for making ethanol, ethylene, propanol, or some other carbon-based chemical, but you would have to go through a lot of steps to separate unwanted, residual chemicals formed during the intermediate stages of a chemical reaction before arriving at your final destination — the chemical end-product.

Read more at DOE/Lawrence Berkeley National Laboratory