PREPARATION AND STUDY OF DECAVANADATE-PILLARED HYDROTALCITE-LIKE ANIONIC CLAYS CONTAINING TRANSITION-METAL CATIONS IN THE LAYERS .2. SAMPLES CONTAINING MAGNESIUM-CHROMIUM AND NICKEL-CHROMIUM
F. Kooli et al., PREPARATION AND STUDY OF DECAVANADATE-PILLARED HYDROTALCITE-LIKE ANIONIC CLAYS CONTAINING TRANSITION-METAL CATIONS IN THE LAYERS .2. SAMPLES CONTAINING MAGNESIUM-CHROMIUM AND NICKEL-CHROMIUM, Inorganic chemistry, 34(21), 1995, pp. 5122-5128
Mg-Cr and Ni-Cr layered double hydroxides (LDHs) with carbonate anions
in the interlayer were used as precursors to synthetize pillared deri
vatives with decavanadate (V10O28)(6-) anions without the use of any p
reswelling agent. Characterization was carried out by powder X-ray dif
fraction, chemical analysis, FT-infrared spectroscopy, thermal analysi
s, and transmission electron microscopy. The influence of the wetness
degree of the starting Mg-Cr and Ni-Cr LDHs and of the pH conditions o
n the anionic-exchange rate of carbonate was studied. The pillared mat
erials were constituted by a well crystalline phase, together with a c
oproduct with a lower degree of crystallinity, characterized by a broa
d X-ray diffraction peak close to 10 Angstrom. Anion-exchange was neit
her achieved without prewetting of the carbonate-containing LDH nor at
pH values larger than 6.5. The thermal stability of the pillared mate
rials and their surface properties are also presented.