Scientists at the U.S. Department of Energy's Ames Laboratory have demonstrated a way to precisely control the chemistry that underpins the transformation of carbon dioxide into either fuels or feedstock chemicals, depending upon slight changes in the catalyst. The findings, reported in the journal Nature Communications, could lead to more efficient processes for recycling CO2 into economically valuable products.

The study focuses on a catalyst based on a metal called cerium. When the catalyst is combined with a small amount of oxygen and heated in the presence of carbon dioxide and hydrogen, it causes a chemical reaction that converts the carbon dioxide into either methanol or formic acid. Methanol is a fuel that can be used in internal combustion engines or fuel cells, while formic acid is a versatile chemical that can be used to make a variety of other products, including fuels and plastics.

The scientists found that they could control the ratio of methanol to formic acid produced by the reaction by carefully controlling the amount of oxygen present in the catalyst. When the oxygen content was low, the reaction produced more methanol. When the oxygen content was high, the reaction produced more formic acid.

"We were able to achieve very high selectivity for either methanol or formic acid, which is important for industrial applications," said Dr. Wenyu Huang, a scientist in the Ames Laboratory's Chemistry and Materials Science and Technology Division and the corresponding author of the paper. "This opens up the possibility of using CO2 as a sustainable feedstock for the production of fuels and chemicals."

The study also shed light on the mechanism by which the catalyst works, which could help scientists design even more efficient catalysts for CO2 conversion.

This research was supported by the U.S. Department of Energy's Office of Science.