FTIRS study of the nature and reactivity of the products of nitromethane transformation on the surface of copper- and cobalt-exchanged ZSM-5 zeolites as 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 isocyanates 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 molecular oxygen, while no reaction with NO was observed. In the course of melamine oxidation, partial oxidation products including isocyanates appear to be produced. The reactivity of melamine and isocyanate depends upon the temperature and nature of transition metal cation, being reasonably high to suggest their role as intermediates in the NOxCH4-SCR. (C) 2000 Elsevier Science B.V. All rights reserved.