Thursday , July 7 2022

Metal nanocatalysts imitate the structure of the enzyme


The international team of researchers conveyed certain structural characteristics of natural enzymes, which provide a particularly high catalytic activity to metal nanoparticles. Because of this, the desired chemical reaction did not occur on the surface of the particles as usual, but in the channels inside the metal particles – and with three times higher catalytic activity. A team from the University of New South Vales, Australia and Ruhr-Universitat Bochum, Germany, reported about these nanoses in Journal of the American Chemical Society, published online September 23, 2018.

Active centers in the channels

In the case of enzymes, the active centers where the chemical reaction takes place are inside. The reaction substances must pass through the channel from the surrounding solution to the active center, where the spatial structure provides particularly favorable reaction conditions. "It is assumed, for example, that the locally altered pH prevails in the channels and that the electronic environment in the active centers is also responsible for the efficiency of natural enzymes," says Professor Wolfgang Schuhmann, head of the Bochum Center for Electrochemical Science.

Channels produced in nickel-platinum particles

In order to artificially imitate enzymatic structures, researchers produced nickel and platinum particles of about 10 nanometers in diameter. They then removed the nickel using a chemical core, where channels were formed. In the last step, they deactivated active centers on the surface of the particles. "This allowed us to only activate the active channel centers," explains Patrick Vilde, Ph.D. candidate at the Center for Electrochemical Sciences. The researchers compared the catalytic activity of the particles produced in this way with the activity of conventional particles with active centers on the surface.

Three times more activity

For the test, the team used a reduction reaction of oxygen, which, among other things, is the basis for the operation of fuel cells. Active centers at the end of the channel catalyzed the reaction three times more efficiently than the active centers on the surface of the particles.

"The results show a huge potential for nanoscale", summarizes Dr. Corina Andronescu, leader of the group at the Center for Electrochemical Sciences. Researchers now want to extend the concept to other reactions, such as electrocatalytic CO2 Reducing and exploring the principles of increased activity in more detail. "We would like to imitate the way in which the enzymes will work even better in the future," Schuhmann adds. "Finally, we hope that the concept will contribute to industrial applications to make energy conversion processes more efficient using electricity produced from renewable sources."


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