Synthesis, characterization and catalytic activity of LayMOx (M=Ni, Co) perovskite-type particles intercalated in clay via heterobinuclear complexes

Clays intercalated with LayMOx (M = Ni, Co) nanospecies with perovskite-type structure have been prepared from heterobinuclear complexes MLa(fsaen)NO3, LaM(H2L)(NO3)(3), and [LaML(NO3)](2). The cationic form of these binuclear complexes was introduced between the clay sheets via an exchange process and a d-space of 17.7-24.8 Angstrom was achieved. After heating and removal of the organic part LayMOx nanospecies were formed and the d-space was around 12.3-14.0 Angstrom. The specific surface area of the fired solids was found to be between 92 and 178 m(2) g(-1), depending on the method of preparation used. The products were investigated by XRD; TG/DTA, specific surface area and acidity (Bronsted/Lewis) measurements, as well as by EDX analysis for their composition. Their catalytic activity was evaluated in the reaction of isopropanol and cracking/isomerisation of heptane. These solids showed essentially dehydrating activity in isopropanol decomposition, and hydrogenolytic activity in heptane reaction. The extent of catalytic conversion for the isopropanol decomposition for the intercalated materials was lower as compared to non-intercalated samples. The conversion for the heptane hydrogenolysis reached similar to 100% at similar to 350 degrees C and proceeds mainly towards cracking rather than isomerization which reached only similar to 8%. (C) 1998 Elsevier Science B.V. All rights reserved.