Exhaust gas catalysis
The current research activities of environmental catalysis focus on the removal of NOx, N2O, CH4, HC, soot and CO from automotive exhaust and flue gases. The major aim is the development of innovative catalysts and techniques for emission control.
A crucial part of the research implies the development of a fundamental understanding of the surface chemistry of iron oxide and manganese oxide catalysts as well as precious metal catalysts such as platinum and palladium. The studies aim to elucidate the nature of the catalytically active sites, reaction mechanism and intrinsic kinetics. Based on this knowledge global and elementary kinetic models are constructed and structure-activity relationships are deduced. These detailed insights provide the targeted development of highly active catalysts and novel techniques for the purification of exhaust gases.
Another important feature of the research is the substitution of the noble metals platinum and palladium, which are widely used in environmental catalysis, by more sustainable materials, e.g. iron and manganese oxides. Furthermore, research also includes tools of chemical reaction engineering to investigate the coupling of the chemical reactions with transport phenomena occurring in the technical reactor systems.
Current projects address the following purification processes:
- NOx reduction by NH3 according to the SCR procedure (Selective Catalytic Reduction) using V2O5/WO3/TiO2, Fe/BEA zeolites and Fe2O3/Al2O3 catalysts for O2-rich engine exhaust and flue gases
- SCR conversion by employing AdBlue for on-board-production of NH3 (urea-SCR)
- NOx reduction by H2 on precious metal catalysts in O2-rich exhaust gases (H2-DeNOx), e.g. for lean H2 combustion engines and low-temperature deNOx in diesel engines
- Decomposition of N2O on Fe2O3/Al2O3 catalysts in flue gases
- Soot oxidation on iron and manganese oxide catalysts in exhaust of diesel and DI gasoline engines
- Oxidation of CO, HC und NO on precious metal and iron oxide catalysts under lean conditions, e.g. diesel exhaust
- CO oxidation under stoichiometric conditions on Pd/Al2O3 three way model catalysts
- Catalytic CH4 and HCHO oxidation in O2-rich exhaust gases, e.g. gas engines
- CH4 oxidation on non-precious metal catalysts for O2 removal from biogas