Cobalt Oxide/Silica Xerogels Powders: X-Ray Diffraction,Infrared and Visible Absorption Studies

Using x-ray diffraction, infrared and visible absorption spectroscopies we have studied: silica xerogel powders when cobalt nitrate is incorporated and mainly the evolution of the precipitated cobalt species in the SiO₂ matrix. Samples containing cobalt nitrate and prepared with a molar ratio of H₂O/TEOS of 11.67 were studied as a function of annealing temperature. It was found that the added element has a remarkable influence on the final structure of this kind of samples and at relatively high temperatures the cobalt compounds react with the silica matrix forming a cobalt silicate.