Preparation and characterisation of cobalt containing layered double hydroxides

A series of hydrotalcites of general formula Co2+-M(3+)-CO3-HT (M(3+) = Al,Fe and Cr) are prepared by coprecipitation technique. The influence of parameters such as preparation method, atomic ratio, supersaturation levels, aging and hydrothermal treatments are investigated to study their effect on the structure and texture of these materials. The obtained materials are characterised by X-ray diffraction, FT-IR studies, thermogravimetry-differential scanning calorimetry, transmission electron microscopy and BET surface area measurements. Thermal calcination of these materials resulted in the formation of high surface area non-stoichiometric spinels whose catalytic activity is studied using N2O decomposition reaction as the test reaction. The order of activity observed is Co-Al-CO3-HT>Co-Fe-CO3-HT>Co-Cr-CO3-HT.