Gn. Kustova et al., IR spectroscopic investigation of cation distribution in Zn-Co oxide catalysts with spinel type structure, J MOL CAT A, 158(1), 2000, pp. 293-296
The structure of Zn-Co spinel prepared by coprecipitation was studied by IR
spectroscopy. The characteristic bands of extra OH- and H3O+ groups were s
hown to exist in IR spectra up to 700 degrees C. Comparing IR spectra of a
poorly crystallized low temperature catalyst with that of a perfect Zn-Co s
pinel, we have associated the noticeable splittings and shifts of the F-1u
bands with definite structural distortions. The presence of extra anions in
the catalyst with a spinel-like structure in the temperature region 100-70
0 degrees C is the factor that stabilized the unusual cation distribution i
n this catalyst. The most plausible cation distribution in such a spinel is
proposed as follows: Co3+ and Zn2+ are in octahedral positions, and Co2+ a
nd Zn2+ are in tetrahedral ones. (C) 2000 Elsevier Science B.V. All rights
reserved.