Comparative Study of the Surface Species over Pt-based and Ag-based Catalysts in SCR of NO by Propene under Lean-burn Condition

摘要

Pt/Al_2O_3 and Ag/Al_2O_3 have been used to remove nitrogen oxides from exhaust gases because they show high efficiency and significant performance for SCR of NO_x by hydrocarbon under excess oxygen. It is well known that the catalytic behavior for both catalysts is definitely different dependent on several parameters. However, the significant image of Pt/Al_2O_3 is the production of a large amount of N_2O, while Ag/Al_2O_3 is a good catalyst to provide N_2 selectivity. To explain the catalytic behavior and improve the catalytic performance, many works have focused on their experimental data to propose the reaction mechanism through observation the surface species, especially application of IR technique. Although those results could answer several problems, there is still other doubtfulness. Hence, the aim of this work is to investigate the surface species that are occurred on Pt/Al_2O_3 and Ag/Al_2O_3 in SCR of NO by propene through another technique, i.e., temperature programmed technique.