Influence of lithium on the kind of cobalt-species formed on γ-Al2O3

Abstract

The effects of calcination temperature and lithium content on the kind of cobalt species formed on the surface of γ-Al2O3 have been studied using diffuse reflectance spectroscopy(D.R.S) and X-ray powder analysis (X.R). Six specimens with various amounts of lithium, all containing 2.8% Co3O4, have been prepared by pore volume impregnation of γ-Al2O3 with lithium nitrate aqueous solutions, followedby pore volume impregnation of the resulting supports with cobalt nitrate aqueoussolutions. A considerable inhibition of the solid-state transformation of Co3O4 into CoAl2O4 with thelithium content wasobserved by R.S.A determination of activation energies, using various models, for the above mentioned solidstatetransformation allows us to shed some light on lithium effects; the practical consequences, from a catalytic point of view, of these effects are also discused. © by Akademische Verlagsgesellschaf

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