A team from the University of Minnesota and University of Houston has directly measured tiny electron shares in catalytic processes, solving a century-old puzzle. Their new technique, called Isopotential Electron Titration (IET), reveals how molecules interact with precious metals like gold, silver, and platinum. The findings, published in ACS Central Science, could accelerate the development of efficient catalysts for energy and manufacturing.
Catalysts are vital in industries such as pharmaceuticals, batteries, and oil refining, where they lower energy needs for chemical reactions to improve speed and efficiency. For over 100 years, scientists knew that molecules exchange small electron portions with metal surfaces during catalysis, but direct measurement of these fractions remained elusive.
The breakthrough came from researchers at the University of Minnesota Twin Cities College of Science and Engineering and the University of Houston's Cullen College of Engineering. Using IET, they quantified electron sharing at catalytic surfaces under relevant conditions. This method provides precise data on bonding, unlike previous indirect approaches in idealized settings.
"Measuring fractions of an electron at these incredibly small scales provides the clearest view yet of the behavior of molecules on catalysts," said Justin Hopkins, a University of Minnesota chemical engineering Ph.D. student and lead author. Precious metals excel because they enable optimal electron transfer, allowing molecules to bind and react effectively.
For instance, a hydrogen atom on platinum shares just 0.2% of an electron, a minute amount that facilitates industrial reactions. "IET allowed us to measure the fraction of an electron that is shared with a catalyst surface at levels even less than one percent, such as the case of a hydrogen atom on platinum," explained Omar Abdelrahman, corresponding author and associate professor in the University of Houston's William A. Brookshire Department of Chemical and Biomolecular Engineering.
This work stems from the Center for Programmable Energy Catalysis, launched in 2022 as part of the U.S. Department of Energy's Energy Frontier Research Centers. The center focuses on advanced dynamic catalysts for materials, chemicals, and fuels. "The foundation for new catalytic technologies for industry has always been fundamental basic research," noted Paul Dauenhauer, the center's director and a distinguished professor at the University of Minnesota. "This new discovery of fractional electron distribution establishes an entirely new scientific foundation for understanding catalysts that we believe will drive new energy technologies over the next several decades."
IET complements nanotechnology and machine learning in catalyst design, enabling faster identification of promising materials.