XAFS characterization of the binuclear iron complex in overexchanged Fe/ZSM5 - structure and reactivity

We have characterized, with emphasis on XAFS spectroscopy, one of the most promising DeNOx catalysts, i.e., Fe/ZSM5 prepared through the FeCl3 sublima tion technique. XAFS is a very useful tool for this purpose since it is ele ment specific and can be used in situ, namely, in the presence of the react ants and at reaction temperature. In this communication it will be pointed out that the as-synthesized Fe/ZSM5 catalyst contains stable binuclear iron oxo/hydroxo-complexes. The reaction of these complexes with the probe mole cule CO clearly shows that only one of the oxygen shells around iron change s while the iron contribution is not affected, the iron complex remaining b inuclear.