Energy researchers exceed the catalytic speed limit

A team of researchers from the University of Minnesota and the University of Massachusetts, Amherst, has discovered a new technology that can accelerate chemical reactions 10,000 times faster than the current limit of reaction rate. These results could increase the speed and reduce the cost of thousands of chemical processes used in the development of fertilizers, food, fuels, plastics, and so on.

The research is published online in Catalysis ACS, a leading newspaper of the American Chemical Society.

In chemical reactions, scientists use what are called catalysts to accelerate reactions. A reaction occurring on a catalyst surface, such as a metal, will accelerate, but it will not be able to go as fast as the Sabatier principle allows. Often called the "Goldilocks principle" of catalysis, the best possible catalyst is to perfectly balance two parts of a chemical reaction. The molecules that react must adhere to a metal surface to react neither too much nor too weakly, but "just right". Since this principle was established quantitatively in 1960, the maximum of Sabatier remained the catalytic speed limit.

Researchers at the US Department of Energy's Catalysis Center for Energy Innovation have discovered that they can exceed the speed limit by applying waves to the catalyst to create an oscillating catalyst. The wave has a top and a base and, when applied, allows both sides of a chemical reaction to occur independently at different speeds. When the wave applied to the surface of the catalyst matches the natural frequency of a chemical reaction, the velocity increases considerably via a mechanism called "resonance".

"We realized early on that the catalysts had to change over time and it turned out that frequencies ranging from kilohertz to megahertz greatly accelerated catalyst levels," said Paul Dauenhauer, professor of chemical engineering and science materials at the University of Minnesota. of the study.

The maximum catalytic speed limit, or Sabatier maximum, is only accessible for some metal catalysts. Other metals that have a weaker or stronger bond have a slower reaction rate. For this reason, plots of catalyst reaction rate versus metal type were called "volcano-shaped traces" with the best static catalyst existing at the center of the volcano's peak.

"The best catalysts have to switch quickly between strong and weak binding conditions on both sides of the volcano diagram," said Alex Ardagh, postdoctoral researcher at the Catalysis Center for Energy Innovation. "If we reverse the binding force fast enough, the catalysts that connect between a strong bond and a weak bond have better performance than the catalytic limit speed."

The ability to accelerate chemical reactions directly affects thousands of chemical technologies and materials used to develop fertilizers, foods, fuels, plastics, and so on. During the last century, these products have been optimized using static catalysts such as supported metals. Improved reaction rates could significantly reduce the number of equipment needed to manufacture these materials and reduce the overall costs of many everyday materials.

The dramatic improvement in catalyst performance can also reduce systems for distributed and rural chemical processes. Because of the savings in large-scale conventional catalyst systems, most materials are only manufactured in huge centralized sites such as refineries. Faster dynamic systems can be smaller processes that can be located in rural areas such as farms, ethanol plants or military installations.

"This could completely change the way we make almost all of our most basic chemicals, materials and fuels," said Professor Dionisios Vlachos, director of the Catalysis Center for Energy Innovation. "The transition from conventional catalysts to dynamic catalysts will be as important as switching from direct electricity to alternative electricity."