PULLMAN, Wash. — A catalyst developed by a Washington State University research team efficiently converts abundant, renewable ethanol into valuable molecules needed for production of plastics, fuels, and everyday products.
The advance could someday make it easier to use renewables rather than petrochemicals to make common products. Led by Regents Professor Yong Wang, the researchers, including from Pacific Northwest National Laboratory (PNNL), report on their work in the journal, Chem Catalysis.
“Right now industry works with petrochemicals, but at some point, it is necessary to transition to renewable sources, and I think this kind of work helps us to better understand and approach using those renewables,” said Vannessa Caballero, co-first author on the paper and a recent PhD graduate in the Gene and Linda Voiland School of Chemical Engineering and Bioengineering.
Modern chemical manufacturing relies on carbon-emitting fossil fuels to produce numerous everyday products, such as plastics, nylon, and fuels. Ethanol, made through fermentation of a wide variety of crops, could be abundant and offers a potentially alternative feedstock for these needed high-value chemicals.
Right now industry works with petrochemicals, but at some point, it is necessary to transition to renewable sources, and I think this kind of work helps us to better understand and approach using those renewables.
Vannessa Caballero, PhD graduate
Washington State University
However, the conversion process for ethanol is inefficient. The conventional catalysts that are used often cause competing reactions, which waste carbon and lowers efficiency of the whole process.
“Making good catalysts is not very hard, but if you want to make them cost-effective and robust in a real reactor — that’s very challenging,” said Wenda Hu, co-first author on the work and a postdoctoral researcher in the Voiland School. “Controlling selectivity is very hard.”
In their work, the researchers dramatically improved a key step in the ethanol conversion process by positioning single atoms of the rare-earth metal cerium inside tiny pores of the crystalline material zeolite.
When cerium atoms are allowed to cluster together, the “reaction veers off course,” generating unwanted byproducts, said Hu. The zeolite pores act as a prison to confine individual cerium atoms. Once isolated, the cerium atoms facilitate what is usually the tricky removal of oxygen and maximize the production of isobutene, a versatile chemical used in the production of numerous products.
“Converting biomass to useful chemicals is very important,” said Hu. “In this work, we found that if we build the zeolite and then we put atoms with precision in this porous material, we can realize very selective and stable production of this useful chemical, isobutene, from biomass-derived chemicals. This discovery demonstrates that the size and placement of atoms inside a catalyst can determine the fate of every reaction step.”
The researchers are continuing the work to improve the catalysts. For instance, they’re looking at combining cerium with another metal to improve the reaction.
“There are some promising, well-isolated atoms that we could probably target to improve the activity during this reaction,” said Caballero.
The work was funded by the Department of Energy’s Office of Science.
“By harnessing atomic-level control to guide these complex reactions, we can provide solutions for economically viable approaches for the production of chemicals from non-fossil fuel-based feedstocks,” said Wang, who holds a joint appointment at PNNL.
Media Contacts
- Yong Wang, Gene and Linda Voiland School of Chemical Engineering and Bioengineering, 509-371-6273, wang42@wsu.edu
- Tina Hilding, Voiland College of Engineering and Architecture Communications, 509-335-5095, thilding@wsu.edu
- Karyn Hede, Pacific Northwest National Laboratory, 509-375-2144, karyn.hede@pnnl.gov
