High efficiency of noble metal and metal oxide catalyst systems for the selective reduction of NO with propene in lean exhaust gas

An investigation was conducted of noble metal and metal oxide catalysts deposited on Al2O3. The noble metals Pt, Pd, Rh the metal oxides CuO, SnO2, CoO, Ag2O, In2O3, catalysts were examined. Also investigated were noble metal Pt, Pd, Rh-doped In2O3/Al2O3 catalysts prepared by single sol–gel method. Both were studied for their capability to reduce NO by propene under lean conditions. In order to improve the catalytic activity and the temperature window, the intermediate addition propene between a Pt/Al2O3 oxidation and metal oxide combined catalyst system was also studied. Pt/Al2O3 and In2O3/Al2O3 combined catalyst showed high NO reduction activity in a wider temperature window, and more than 60% NO conversion was observed in the temperature range of 300–550 °C.