NO_x removal efficiency and N₂ selectivity during selective catalytic reduction processes over Al₂O₃ supported highly cross-linked polyethylene catalysts

The performance of a highly cross-linked polyethylene catalyst supported on alumina for low temperature selective catalytic reduction of NO_x by unburned hydrocarbons (HCs) existing in an exhaust gas was examined at different engine conditions with the addition of exhaust-gas recirculation. The HXPE catalyst was shown to exhibit good NO_x reduction activity at low temperatures (100-250°C) where the only reductant was the unburned HC, which was already present in the exhaust flow. The maximum NO_x reduction of approximately 52% was achieved at a temperature of 150°C. HXPE demonstrated very good selectivity toward N₂ in the majority of tested conditions (~80%).