Tajima Prize for Kai S. Exner
How Catalysts Change Under Voltage
- von Juliana Fischer
- 08.10.2026
Prof. Dr. Kai S. Exner, a chemist at the University of Duisburg-Essen, has been awarded the 2026 Tajima Prize by the International Society of Electrochemistry. The award recognises his theoretical research into electrocatalysis. A recent article in Accounts of Materials Research brings together his team's findings on a central question: how do catalysts change under actual reaction conditions?
Catalysts help speed up chemical reactions without being consumed themselves. In electrocatalysis, this is important, for example, when electricity is used to produce hydrogen or convert nitrogen compounds. The efficiency of these processes depends largely on what happens at the catalyst's surface.
This is precisely what Exner's team investigates – using computer simulations at the atomic level. The focus is on so-called MXenes, extremely thin materials that consist of metals such as titanium or molybdenum combined with carbon or nitrogen, among other elements. When an electrical voltage is applied, their surface can rearrange: individual metal atoms emerge and form sites at which chemical reactions can proceed particularly well.
"Our work shows that under an applied voltage the surface restructures – the actual catalyst is only created during operation. Once you understand this, you can design materials so that precisely the desired active sites form," says Exner.
His group first described the basic idea in late 2024 in the Journal of the American Chemical Society. Since then, the researchers have pursued the concept further using computational methods – for oxygen and chlorine evolution, nitrogen reduction and ammonia oxidation, among other reactions.
The article now published in Accounts of Materials Research consolidates this work. Its central message: a catalyst's performance is determined not only by the starting material. Just as important is which active state actually forms during the reaction. Voltage and pH can help determine which atomic structures emerge.
The Tajima Prize honours the published research achievements of electrochemists under the age of 40. For the first time in ten years, the award goes to a researcher at a German institution. In 2027, Exner will present his work in an award lecture at the annual meeting of the International Society of Electrochemistry in Glasgow.
Further information
Original publication in Accounts of Materials Research: https://doi.org/10.1021/accountsmr.6c00164
Prof. Dr. Kai S. Exner, Theoretical Catalysis and Electrochemistry, phone +49 201 183-2992, kai.exner@uni-due.de