New Light-Activated Catalyst That Turns CO2 into Fuel

Scientists at the Lawrence Berkeley National Laboratory (Berkeley Lab) and Nanyang Technological University (NTU) in Singapore have developed a light-activated material that can chemically convert carbon dioxide (CO2) 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 CO2 in a reaction chamber exclusively into Carbon Monoxide (CO) gas, which can be further turned into liquid fuels, solvents, and other useful products.

The research is published 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. That’s a big deal. In CO2 reduction, you want to come away with one product, not a mix of different things,” said Haimei Zheng, staff scientist in Berkeley Lab’s materials sciences division and co-corresponding author of the study.

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 CO2 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 the 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.

Researchers developed an innovative laser chemical method of creating a metal-organic composite material.

They dissolved nickel precursors in a solution of triethylene glycol and exposed the solution to an unfocused infrared laser, which set off a chain reaction in the solution as the metal absorbed the light. The resulting reaction formed metal-organic composites that were then separated from the solution.

“When we changed the wavelength of the laser, we would get different composites. That’s how we determined that the reactions were light-activated rather than heat-activated,” said study co-lead author Kaiyang Niu, a materials scientist in Zheng’s lab.

“The world right now is in need of innovative ways to create alternatives to fossil fuels and to stem the levels of excessive CO2 in the atmosphere. Converting CO2 to fuels using solar energy is a global research endeavour. The spongy nickel-organic photocatalyst we demonstrated here is a critical step toward practical production of high-value multi-carbon fuels using solar energy.” said Zheng

Other authors on this paper include co-corresponding author Rong Xu, NTU associate professor of chemical and biomedical engineering; You Xu, NTU research fellow in Xu’s lab; visiting scholar Haicheng Wang and scientist Joel Ager at Berkeley Lab’s Materials Sciences Division; and Karen Bustillo, a scientific engineer at the Molecular Foundry.