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Colorado State University researchers have a paper in Science that describes a new and more efficient light-based process for transforming fossil fuels into useful modern chemicals. In it, they report that their organic photoredox catalysis system is effective, even at room temperature. That advantage could lower energy demands around chemical manufacturing in a variety of instances and could also reduce associated pollution, among other benefits.

The work is led at CSU by professors Garret Miyake and Robert Paton from the Department of Chemistry and the Center for Sustainable Photoredox Catalysis (SuPRCat).

The system—inspired by photosynthesis—uses visible light to gently alter the properties of chemical compounds. It does this by exposing them to two separate photons (light particles) to generate energy needed for the desired reactions. A single photon does not normally carry enough energy for these processes, said Miyake. By combining energy from two light particles, the team's system can perform super-reducing reactions—chemical changes that require a lot of energy to break tough bonds or add electrons—easily.

Miyake said their system was tested on a group of chemical compounds called aromatic hydrocarbons—otherwise known as arenes. These compounds are usually resistant to change.

"This technology is the most efficient system currently available for reducing arenes—such as benzene in fossil fuels—for the production of chemicals needed for plastics and medicine," Miyake said. "Usually, generating these reactions is difficult and energy intensive because the original bonds are so strong."

The research continues work being done through the U.S. National Science Foundation Center for Sustainable Photoredox Catalysis at CSU. Miyake is the director of that multi-institution research effort to transform chemical synthesis processes across many uses.

Katharine Covert, program director for the NSF Centers for Chemical Innovation program, said photoredox catalysis has become indispensable for many industries.

"Photoredox catalysis has become indispensable for pharmaceutical development and other industries," said Covert. "Through the NSF Center for Sustainable Photoredox Catalysis, synthetic and computational chemists have teamed up to understand the fundamental chemical nature of how those catalysts function, and in so doing, found a new path that requires less heat and energy."

Miyake said researchers across the center are developing catalysis systems similar to the one described in this paper to support energy-efficient production of ammonia for fertilizers, the breakdown of PFAS forever chemicals, and the upcycling of plastics.

"We built an all-star team of chemists to address these challenges and make a more sustainable future for this world," Miyake said. "The world has a time clock that is expiring, and we must meet the urgent need for developing sustainable technologies before our current ways of doing things put us in a place that we can't recover from."

CU Boulder Professor Niels Damrauer is also an author on the paper and a member of the center. Other CSU authors include Amreen Bains, Brandon Portela, Alexander Green, Anna Wolff and Ludovic Patin.