COPPER CLUSTERS IN MORDENITE - A DIRECT STRUCTURAL COMPARISON WITH THE NO DECOMPOSITION CATALYST CU-ZSM-5

Using computer simulation techniques we have identified the configurat ion and location of copper clusters in Cu-mordenite. Fundamental diffe rences are found between these clusters and those generated in an anal ogous modelling study of Cu-ZSM-5, which, considering the structural s imilarity between these two zeolitic materials, suggests that the host lattice exerts a critical influence on the configurations of the copp er species that form within its internal pore structure. We observe a much reduced occurrence of Cu-II-OH-Cu-I species, which we suggested p reviously represents a useful model for the active site in Cu-ZSM-5 an d which may therefore provide a structural explanation for the much re duced activity of Cu-mordenite compared with Cu-ZSM-5 for NO decomposi tion.