The activity of Cu/SiO2, Cu/Vycor and Cu/ZSM-5, and V2O5/TiO2 catalysts for NO conversion to N2 in the presence or absence of NH3 and/or O2 were investigated. The Cu/ZSM-5 catalyst exhibited the highest activity, even higher than that of V2O5/TiO2. Photoluminescence studies of the dehydrated Cu-based catalysts suggested that the copper ions anchored onto ZSM-5 are isolated Cu species near Broensted acid sites in the zeolite channels while the copper ions anchored onto Vycor and SiO2 are present mainly as copper dimer forms. These results suggest the role of copper ions, which are stabilized by neighboring O vacancies created by dehydroxylation of the zeolite, in NO conversion. The isolated Cu ions near Broensted acid sites play a significant role in NO conversion but dimeric or polynuclear Cu species are less effective for the reaction. [on SciFinder(R)]
Role of the nature of copper sites in the activity of copper-based catalysts for nitric oxide conversion
CENTI, Gabriele;PERATHONER, Siglinda;
1992-01-01
Abstract
The activity of Cu/SiO2, Cu/Vycor and Cu/ZSM-5, and V2O5/TiO2 catalysts for NO conversion to N2 in the presence or absence of NH3 and/or O2 were investigated. The Cu/ZSM-5 catalyst exhibited the highest activity, even higher than that of V2O5/TiO2. Photoluminescence studies of the dehydrated Cu-based catalysts suggested that the copper ions anchored onto ZSM-5 are isolated Cu species near Broensted acid sites in the zeolite channels while the copper ions anchored onto Vycor and SiO2 are present mainly as copper dimer forms. These results suggest the role of copper ions, which are stabilized by neighboring O vacancies created by dehydroxylation of the zeolite, in NO conversion. The isolated Cu ions near Broensted acid sites play a significant role in NO conversion but dimeric or polynuclear Cu species are less effective for the reaction. [on SciFinder(R)]Pubblicazioni consigliate
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