Exner studies electrochemical reactions on solid-state catalysts. These processes play a crucial role for a sustainable energy supply, for example to split water into oxygen and the energy carrier hydrogen. He developed new models for predicting the performance of electrode materials, which help identify new combinations for catalyst materials and optimize materials. Costly "trial and error" tests can thus be avoided. Exner has also applied concepts from catalysis research to optimize drug delivery systems in cancer therapy.
Exner studied chemistry at Justus Liebig University in Giessen, where he received his doctorate in physical chemistry in 2015. He then conducted postdoctoral research at the universities of Ulm, Giessen and Sofia, Bulgaria, before joining the University of Duisburg-Essen (UDE). Since 2021, he has been a junior professor (W1 with tenure track to W2) with a focus on Theoretical Inorganic Chemistry at UDE to strengthen the Collaborative Research Center 247 "Heterogeneous Oxidation Catalysis in the Liquid Phase". The young researcher, who has already published over 50 papers, has already received several awards for his work.