Kinetic and in situ DRIFT spectroscopy studies of NO oxidation,and reduction by C_3H_6 in excess O_2 over gamma -Al_2O_3 and Au/ gamma -Al_2O_3

摘要

The in situ DRIFT spectroscopy studies of NO and NO_2 SCR were performed on gamma -Al_2O_3 and Au/ gamma -Al_2O-3.The obtained results indicate that the initiation of No SCR on Au/ gamma -Al_2O_3 involves the oxidation of NO to NO_2 at active centers at the interface between Au and Al_2O-3 followed by coupling of the NO-2 or its adspecies.NO-_x,with activated C_3H_6 on active sites on Al_2O_3 to form C_nH_mN_xO_y species,which are responsible for the propagation step.Its subsequent internal rearrangement and decomposition leadsto the formation of N_2 and other other products.Taken together,the obtained results suggest that the No_2 intermediacy benefits the NO SCR over gold catalysts as a reaction initiator or oxygen transfer agent.