Plasma-Enhanced Adsorption and Reduction on Lean NOx-Catalysts 2001-01-3567

The influence of adsorption and desorption processes on the non-thermal plasma enhanced catalytic reduction of NO_x on NaZSM5- and Al₂O₃-based lean-NO_x catalysts (Pt-NH₄ZSM5, Cu-NaZSM5, Fe-NaZSM5, Pt-Al₂O₃, Pd-Al₂O₃, CuO-Al₂O₃, Ag-Al₂O₃) was investigated by temperature programmed reaction experiments in the temperature range from 100 °C to 600 °C. Dodecane was used as a reducing agent. Strong HC adsorption- and desorption effects were observed on the zeolite catalysts, which were not influenced by plasma-pretreatment. Adsorption of NO₂ and desorption of NO occurred on Al₂O₃-based catalysts. By plasma-pretreatment adsorption of NO₂ was induced at low temperatures. NO_x-reduction rates of the catalysts Cu-NaZSM5, Fe-NaZSM5, and the Ag-Al₂O₃ were increased substantially by plasma-pretreatment. Both plasma-induced and catalytic oxidation of HCs were limiting factors of the NO_x-reduction obtained on these catalysts.