ON THE VITAL ROLES OF ZEOLITIC MATRIX IN CATALYSTS FOR DENO(X) REACTIONS UNDER CONDITIONS SIMILAR TO DIESEL-ENGINE EXHAUST

The physical and chemical properties of a Cu-ion-exchanged Al-silicate with an MFI or A structure and Cu-containing silicate, in which Cu was incorporated into MFI or A structure were compared. It was found that the stability and catalytic performance of Cu-containing silicates were superior to those of Cu-ion exchanged Al-silicates. Furthermore, the advantageous factors of zeolite materials for deNO(x) reaction were investigated by simulating the acid properties and the thermal stability of the framework. Such metal-containing silicate catalysts have large potentials as the deNO(x) catalysts for diesel engine exhaust. The reaction characteristic was explained by the microscopic sequential reaction (MSR) mechanism.