Johannes Schwank

Our research program is focused on fundamental and applied research problems in heterogeneous catalysis, sensors, and energy storage materials. A major theme is the development of correlations between surface structure of materials and their reactivity. The laboratories are equipped with comprehensive catalyst and materials characterization facilities.

In the area of heterogeneous catalysis, we focus on correlations between the catalyst structure and composition and catalytic function in reactions of industrial importance. Principles of nucleation, clustering, and growth of small particles on support materials are under investigation, with emphasis on bimetallic catalyst systems and oxide catalysts. Of particular interest are geometric and electronic interactions between catalyst components as a means to modify catalytic activity and selectivity. A major thrust of our research efforts is the characterization of supported catalysts by analytical and high-resolution electron microscopy. The microstructural characterization results are then brought into context with X-ray diffraction, atomic absorption, neutron activation analysis, gas chemisorption and X-ray photoelectron spectroscopy data. In-situ spectroscopic techniques such as Fourier-Transform infrared spectroscopy are utilized to monitor adsorbed surface species under reaction conditions. These characterization data are then used to interpret kinetic results for hydrogen or oxygen transfer reactions obtained in flow reactors. Current catalysis projects include autothermal reforming of hydrocarbons, direct reforming solid oxide fuel cell catalysts, automotive emission control catalysis, Fischer-Tropsch catalysis, partial oxidation of hydrocarbons, photocatalytic oxidation and water splitting, and biomass conversion.

In the area of sensors, our group has developed microelectronic gas sensors for a wide range of important applications, from monitoring the purity of microelectronic processing gases to environmental sensing and automotive exhaust gas sensing and diesel particulate sensing. Chemical species are detected on the basis of several principles, including gas adsorption-induced resistance and work function changes.