E-Mail IMAGE: Analysis of a cerium oxide catalyst using carbon monoxide probe molecules and infra-red reflection absorption spectroscopy. view more Credit: (Figure: IFG/KIT) Catalysts are indispensable for many technologies. To further improve heterogeneous catalysts, it is required to analyze the complex processes on their surfaces, where the active sites are located. Scientists of Karlsruhe Institute of Technology (KIT), together with colleagues from Spain and Argentina, have now reached decisive progress: As reported in Physical Review Letters, they use calculation methods with so-called hybrid functionals for the reliable interpretation of experimental data. (DOI: 10.1103/PhysRevLett.125.256101). Many important technologies, such as processes for energy conversion, emission reduction, or the production of chemicals, work with suitable catalysts only. For this reason, highly efficient materials for heterogeneous catalysis are gaining importance. In heterogeneous catalysis, the material acting as a catalyst and the reacting substances exist in different phases as a solid or gas, for instance. Material compositions can be determined reliably by various methods. Processes taking place on the catalyst surface, however, can be detected by hardly any analysis method. "But it is these highly complex chemical processes on the outermost surface of the catalyst that are of decisive importance," says Professor Christof Wöll, Head of KIT's Institute of Functional Interfaces (IFG). "There, the active sites are located, where the catalyzed reaction takes place."