Feb 18 2020
Researchers have developed a durable and economical catalyst for recycling greenhouse gases into components that can be used in hydrogen gas, fuel, and other chemicals. The study represents a significant step toward a circular carbon economy.
Professor Cafer T. Yavuz (left), Ph.D. Candidate Youngdong Song (center), and Researcher Sreerangappa Ramesh (right). Image Credit: Korea Advanced Institute of Science and Technology.
According to the researchers, the outcomes of this study, which was reported in the Science journal on February 14th, could be path-breaking in the attempts to reverse global warming.
We set out to develop an effective catalyst that can convert large amounts of the greenhouse gases carbon dioxide and methane without failure.
Cafer T. Yavuz, Study Author and Associate Professor of Chemical and Biomolecular Engineering and of Chemistry, KAIST
Synthesized from economical and plentiful nickel, molybdenum, and magnesium, the catalyst initiates and accelerates the rate of reaction for converting methane and carbon dioxide into hydrogen gas. It has the ability to work effectively for over a month.
This conversion, named “dry reforming,” involves processing hazardous gases like carbon dioxide to synthesize more useful chemicals that could be refined for use in plastics, fuel, or even pharmaceuticals. Although this process is effective, earlier, it necessitated high-cost and rare metals like rhodium and platinum to initiate a brief, inefficient chemical reaction.
Earlier, other researchers had suggested nickel as a more cost-effective solution. However, there would be an accumulation of carbon byproducts and the surface nanoparticles would attach together on the inexpensive metal, drastically changing the geometry and composition of the catalyst and making it ineffective.
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.
Cafer T. Yavuz, Study Author and Associate Professor of Chemical and Biomolecular Engineering and of Chemistry, KAIST
The team synthesized nickel-molybdenum nanoparticles under a reductive atmosphere in the presence of a single crystalline magnesium oxide. Upon heating the ingredients under reactive gas, the nanoparticles shifted to the pristine crystal surface looking for anchoring points.
The result was an activated catalyst that enclosed its own high-energy active sites and permanently set the location of the nanoparticles. This implies that there is no accumulation of carbon in the nickel-based catalyst, and the surface particles do not bind to each other.
It took us almost a year to understand the underlying mechanism. Once we studied all the chemical events in detail, we were shocked.
Youngdong Song, Study First Author and Graduate Student, Department of Chemical and Biomolecular Engineering, KAIST
The catalyst was named Nanocatalysts on Single Crystal Edges (NOSCE) by the researchers. The magnesium-oxide nanopowder is formed from a type of magnesium oxide that is finely structured, in which the molecules bind continuously to the edge. Since there are no defects or breaks in the surface, predictable and uniform reactions can be ensured.
“Our study solves a number of challenges the catalyst community faces,” added Yavuz. “We believe the NOSCE mechanism will improve other inefficient catalytic reactions and provide even further savings of greenhouse gas emissions.”
This work was supported, in part, by the Saudi-Aramco-KAIST CO₂ Management Center and the National Research Foundation of Korea.
Ercan Ozdemir, Sreerangappa Ramesh, Aldiar Adishev, and Saravanan Subramanian, all affiliated with the Graduate School of Energy, Environment, Water and Sustainability at KAIST; Aadesh Harale, Mohammed Albuali, Bandar Abdullah Fadhel, and Aqil Jamal, all affiliated with the Research and Development Center in Saudi Arabia; and Dohyun Moon and Sun Hee Choi, both affiliated with the Pohang Accelerator Laboratory in Korea, are other contributors to this study.
Ozdemir is also affiliated with the Institute of Nanotechnology at the Gebze Technical University in Turkey; Fadhel and Jamal are also affiliated with the Saudi-Armco-KAIST CO₂ Management Center in Korea.