REMOVAL OF NITRIC-OXIDE ON METALLOSILICATE CATALYSTS

The catalytic conversion of NO under O-2 excess conditions with the addition of a low concentration of hydrocarbons was investigated. The stability of the catalyst structure was compared between ion-exchanged ZSM-5 and Cu-incorporated silicate having MFI structure (metallosilicate). The advantage of metallosilicate is emphasized. The performance of various kinds of metallosilicates for NO conversion was evaluated and it was found that metallosilicates such as H-Co-silicate which has a proper acid strength and redox capacity, in other words, a proper activity for hydrocarbon conversion and hydrocarbon combustion, were the best catalysts for the purpose. The reaction characteristics on the metallosilicate catalysts were explained by the microscopic sequential reaction (MSR) mechanism.