Bein, Thomas; Schmidt, Friedrich; Gunsser, W.; Schmiester, G.
Substrate effect on the growth of iron clusters in Y zeolite.
In: Surface Science, Vol. 156, No. 1: pp. 57-63
Investigation of the decomposition process and of the thermolytic products obtained from Fe(CO)5/faujasite adducts by thermogravimetric, IR-spectroscopic, Mössbauer spectroscopic and X-ray absorption measurements (EXAFS) provides evidence for a substrate effect on the growth process of iron clusters. CsY substrate increases the Fe---CO bond strength. The stabilized intermediates generated by this effect upon thermolysis at 500 K are easily oxidized to small iron(III) oxide clusters, whereas with NaY substrate to a large extent iron(O) particles are generated. The latter show Mössbauer effect and EXAFS spectra comparable to those obtained from bulk iron. An inner oxidation process is assumed to be involved in the generation of the zeolite-supported iron oxide.