Cobalt sites in zeolites FAU - IR investigations

The properties of Co2+ in zeolites CoX and CoY and their interaction with CO, NO, and propene were followed. The IR experiments of CO and NO informed on the electron acceptor properties of Co2+ sites and the influence of framework composition and of geometry of Co2+ environment on the properties of Co2+. It has been found, that the activation of CO and NO is realized mostly by π back donation, on the other hand, the activation of CC double bond in propene is realized by π donation. The strength of molecules to Co2+ bonding was followed in desorption experiments. It has been found, that σ donation in the case of CO and π donation has more important impact to the strength of molecule to Co2+ bonding.