Catalyst recycles greenhouse gases into hydrogen gas, fuel, other chemicals

By Brooks Hays SCIENCE NEWS FEB. 17, 2020 / 11:30 AM


Researchers have developed a new catalyst that turns greenhouse gases into the ingredients needed to make hydrogen fuel. Photo by Korea Advanced Institute of Science and Technology

Feb. 17 (UPI) -- Scientists have developed a new catalyst that can turn greenhouse gases into hydrogen fuel and other chemicals.

Researchers and policy makers continue to hold out hope that hydrogen fuel, which doesn't emit CO2, can replace traditional fuels.




Engineers have already created a variety of ways to convert CO2 and other gases into hydrogen, but many require relatively rare and expensive elements. Other catalysts trigger brief chemical reactions, limiting their potential.

The catalyst developed by a team of researchers from Turkey, Saudi Arabia and South Korea, is longer-lasting and more economical.

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"We set out to develop an effective catalyst that can convert large amounts of the greenhouse gases carbon dioxide and methane without failure," lead study author Cafer T. Yavuz, associate professor of chemical and biomolecular engineering and of chemistry at the Korea Advanced Institute of Science and Technology, said in a news release.

The catalyst is composed of nickel, magnesium and molybdenum, all of which are abundant and relatively cheap. The catalyst, which works for more than a month, triggers chemical reactions that can convert CO2 and methane into hydrogen gas.

Previously, when researchers used nickel to catalyze reactions, carbon byproducts would accumulate, bind with nanoparticles on the surface of the catalyst and alter the reaction process.

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"The difficulty arises from the lack of control on scores of active sites over the bulky catalysts surfaces because any refinement procedures attempted also change the nature of the catalyst itself," Yavuz said.

For the new catalyst, scientists paired nickel-molybdenum nanoparticles with a single crystalline magnesium oxide, both sealed in a reductive environment, which is an environment free of oxygen and other oxidizing gases.

When heated with a reactive gas, the nanoparticles migrated across the crystalline surface seeking clean anchoring points. The catalyst, excited by the heat, produced its own high-energy active sites, locking the nanoparticles in place. The process prevented the nickel-based catalyst from acquiring carbon buildup.

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"It took us almost a year to understand the underlying mechanism," said study author Youngdong Song, a graduate student in the department of chemical and biomolecular engineering at KAIST. "Once we studied all the chemical events in detail, we were shocked."

Because the nanoparticles bind continuously to the edge of the single-crystalline magnesium oxide, there are no breaks or deformities along the surface to disrupt the reaction process. As a result, the chemical reactions are precise and predictable.

Scientists dubbed the novel method "Nanocatalysts On Single Crystal Edges," or NOSCE.

The "technique could lead to stable catalyst designs for many challenging reactions," scientists wrote in their paper on the discovery, published in the journal Science.