An x-ray photoelectron study of metal clusters in zeolites

The adsorption and decomposition of the volatile carbonyl complexes Mo(CO){sub 6}, Fe(CO){sub 5}, Co{sub 2}(CO){sub 8}, and Co(CO){sub 3}NO in various zeolites has been studied by XPS. Mo(CO){sub 6} produces highly dispersed zerovalent clusters in zeolites NaY, NaX, and KL, and a mixture of oxidized species in LaY. Fe(CO){sub 5} produces initially zerovalent clusters in NaY, but these migrate to the external surface on heating to higher temperatures. Migration of iron out of the zeolite is inhibited by exchanging divalent cations Co{sup 2+} and Ni{sup 2+} into the zeolite. Co{sub 2}(CO){sub 8} decomposes extensively on the external surface of NaY and NaX, but the mononuclear complex Co(CO){sub 3}NO is readily adsorbed into NaY; decomposition produces a mixtures of zerovalent and oxidized cobalt species.