SYNTHESIS AND FEATURES OF BINARY COBALTITE SPINELS

The main developments in the synthesis of cobaltites are surveyed. Sol id state reactions between oxides, thermal decomposition of mechanical mixtures of transition metal salts, the use of complex compounds as p recursors, mechanochemical synthesis, deposition of cobaltites on supp orts and cobaltite synthesis by thermal treatment of coprecipitated co mpounds are discussed and the specific advantages and disadvantages of each method pointed out. The binary spinel cobaltites find applicatio ns as materials in many fields, their main importance being as catalys ts. In order to achieve high specific surface area, cobaltite synthesi s by thermal treatment of coprecipitated precursors proves to be the m ost promising method. Different kinds of precursors are regarded. Tran sition metal basic salts are promising for the synthesis of binary mix ed oxides and, in particular, of cobaltites. The conditions suited by the coprecipitated precursors for the synthesis of cobaltites with pre set properties, such as high-dispersity, homogeneity, a definite stoic hiometry and a low impurity content, are indicated. Special attention is paid to hydroxidecarbonates. Their use as precursors ensures these demands for the final product and also evolution of toxic gases during the thermal decomposition is avoided.