48 research outputs found
Reactivity theory of zinc cation species in zeolites
Various forms of zinc cation stabilisation in zeolite cavities were considered. Their interaction with light alkanes (methane, ethane) was studied using ab initio methods. We studied the relation between stability of a site and its catalytic activity. In addition to cationic positions formed by a zeolitic ring with two AI ions, the sites with distantly placed aluminiums were also studied. It was shown that the latter tend to form oxygen bridged zinc cationic pairs. Such sites, as well as small zinc oxide clusters, exhibit a different enhanced reactivity towards alkanes compared to single zinc ions in cationic positions