July 8, 2019
Chemical and Biomolecular Engineering Professor David Flaherty has received a new grant from the U.S. Army to develop design rules for solid catalysts for selective oxidations in the liquid-phase.
“To do that, we need to understand how to engineer the electronic structure of atomically dispersed transition metal active sites on oxide supports, which depend on the metals that form the active sites and the manner by which they share electrons with the extended surface of the support,” Flaherty said.
The motivation for the research comes from the wide-spread need for epoxides for the production of advanced materials, industrial solvents, and common consumer goods. The epoxidation of light alkenes (unsaturated hydrocarbons), produced in high volume from traditional fossil reserves and now shale gas, provides reactive building blocks that confer unique properties to polymers and surfactants. As a result, epoxides are produced on a massive scale; the global production and market for ethylene oxide and propylene oxide alone exceeds $45 billion each year.
“We should be able to control rates and selectivities for epoxidation reactions by electronically modifying the active sites for these reactions through use of different isolated metal atoms or by placing these metal atoms onto surfaces that act like ligands and change their electronic properties,” Flaherty said.
The new grant will fund the building of an apparatus that will allow the lab to characterize the structure of the active site and catalytic intermediates while the reaction is occurring, rather than relying on ex situ characterization methods that are unable to provide the needed information. This problem is well-known, according to Flaherty, as catalysts are dynamic, seemingly animate objects whose appearance and behavior depends strongly on their surroundings. Therefore, in situ characterization is required to learn about the active form of the catalyst.
“The general principles established under this project may enable rational catalyst design towards more reactive and selective catalysts,” said Dawanne Poree, program manager, chemical science, Army Research Office, an element of the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory. “These type of materials could be of great value to the Army, for efficient decomposition of hazardous chemicals for personnel and equipment protection.”
Since 2016, the Flaherty lab has received support from the Army Research Office for its research in this area. The funding for this project, and other projects inspired by the findings, has supported several graduate students and a postdoctoral researcher in the lab and has led to the publication of five articles in highly regarded journals (J. Am. Chem. Soc. ACS Catalysis, J. Catalysis) since 2017.
Flaherty joined the University of Illinois Department of Chemical and Biomolecular Engineering in 2012. He earned his Ph.D. from the University of Texas at Austin in 2010 and his post-doctoral work was completed at the University of California, Berkeley. His lab focuses on the overlapping topics of catalysis, surface science, and materials synthesis.