FTIRS study of the nature and reactivity of the products of nitromethane transformation on the surface of copper- and cobalt-exchanged ZSM-5 zeolitesas related to the mechanism of NOxCH4-SCR

For Cu- and Co-ZSM-5, at temperatures around 300 degrees C, the adsorption of nitromethane followed by its acid-catalyzed transformation into isocyana tes and melamine as well as the reactivity of these species with respect to oxygen and NO were studied by FTIRS. Both species easily interact with mol ecular oxygen, while no reaction with NO was observed. In the course of mel amine oxidation, partial oxidation products including isocyanates appear to be produced. The reactivity of melamine and isocyanate depends upon the te mperature and nature of transition metal cation, being reasonably high to s uggest their role as intermediates in the NOxCH4-SCR. (C) 2000 Elsevier Sci ence B.V. All rights reserved.