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Creating a Circular Economy Using Greenhouse Gases

Scientists from the Korea Advanced Institute of Science and Technology (KAIST) have developed a catalyst that recycles greenhouse gases into fuel and hydrogen gas.

In the study published on 14 February 2020 in Science the researcher outlined the mechanism of the catalyst in “dry reforming” greenhouse gases such as methane with carbon dioxide to a mixture of hydrogen and carbon monoxide.

“We set out to develop an effective catalyst that can convert large amounts of the greenhouse gases carbon dioxide and methane without failure,” said Cafer T. Yavuz, paper author and associate professor of chemical and biomolecular engineering and of chemistry at KAIST.

The catalyst is made from inexpensive and abundant nickel, magnesium, and molybdenum. It initiates and speeds up the rate of reaction in the conversion of carbon dioxide and methane into hydrogen gas. It is able to work efficiently for more than a month before being replaced.

Using the process of “dry reforming”, more useful chemicals could be refined for use in fuel, plastics, or even pharmaceuticals. This process previously required rare and expensive metals such as platinum and rhodium to induce a chemical reaction.

Researchers then proposed the use of nickel, a more economical options. But carbon by-products would build up and the surface nanoparticles would bind together on the nickel, fundamentally changing the composition and geometry of the catalyst and rendering it useless.

“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.

The researchers produced nickel-molybdenum nanoparticles under a reductive environment in the presence of a single crystalline magnesium oxide. As the ingredients were heated under reactive gas, the nanoparticles moved on the pristine crystal surface seeking anchoring points. The resulting activated catalyst sealed its own high-energy active sites and permanently fixed the location of the nanoparticles — meaning that the nickel-based catalyst will not have a carbon build up, nor will the surface particles bind to one another.

The researchers dubbed the catalyst Nanocatalysts on Single Crystal Edges (NOSCE). The magnesium-oxide nanopowder comes from a finely structured form of magnesium oxide, where the molecules bind continuously to the edge. There are no breaks or defects in the surface, allowing for uniform and predictable reactions.

The team believes that their study will help to solve a number to challenges faced by the catalyst community and that the NOSCE mechanism will improve other inefficient catalytic reactions and provide reduction of greenhouse gases emissions. [APBN]