EXAFS and XANES characterization of silicate-oxide nanocomposites

Abstract X ray absorption edges and preedges together with Fourier transforms of the EXAFS signal of the LaCo(fsa)2en,NO3 complex ((fsa)2en ˭N,N′-bis(3-carboxysalicydene)ethylenediamine) alone or intercalated in montmorillonite and taeniolite have been studied as a function of temperature. A preferential orientation of the complex has been found when it is intercalated in the silicates. Upon applying thermal treatment, it undergoes similar decomposition whatever it is free or in taeniolite. Due to the thermal stability of taeniolite layers, a taeniolite-LaCoO3 layered nanocomposite could be formed. On the other hand, we have shown that being in montmorillonite, the cobalt oxide phase is reduced progressively above 270°C.