Credit: Kaiyang Niu and Haimei Zheng/Berkeley Lab
Scientists have developed a light-activated material that can chemically convert carbon dioxide into carbon monoxide without generating unwanted byproducts. The achievement marks a significant step forward in developing technology that could help generate fuel and other energy-rich products using a solar-powered catalyst while mitigating levels of a potent greenhouse gas.
When exposed to visible light, the material, a "spongy" nickel organic crystalline structure, converted the carbon dioxide (CO2) in a reaction chamber exclusively into carbon monoxide (CO) gas, which can be further turned into liquid fuels, solvents, and other useful products.
An international research team led by scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and Nanyang Technological University (NTU) in Singapore published the work July 28 in the journal Science Advances.
"We show a near 100 percent selectivity of CO production, with no detection of competing gas products like hydrogen or methane," said Haimei Zheng, staff scientist in Berkeley Lab's Materials Sciences Division and co-corresponding author of the study. "That's a big deal. In carbon dioxide reduction, you want to come away with one product, not a mix of different things."
Getting rid of the competition
In chemistry, reduction refers to the gain of electrons in a reaction, while oxidation is when an atom loses electrons. Among the well-known examples of carbon dioxide reduction is in photosynthesis, when plants transfer electrons from water to carbon dioxide while creating carbohydrates and oxygen.
Carbon dioxide reduction needs catalysts to help break the molecule's stable bonds. Interest in developing catalysts for solar-powered reduction of carbon dioxide to generate fuels has increased with the rapid consumption of fossil fuels over the past century, and with the desire for renewable sources of energy.
Researchers have been particularly keen on eliminating competing chemical reactions in the reduction of carbon dioxide.
"Complete suppression of the competing hydrogen evolution during a photocatalytic CO2-to-CO conversion had not been achieved before our work," said Zheng.