Controlled Architecture of Solids with Micro-Porosity and Meso-Porosity Obtained by Pillaring of Montmorillonite with an Laniox Binary Oxide
(EN)
Skaribas, S. P.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Skaribas, S. P.
(EN)
High-surface-area solids containing both micropores and mesopores have been synthesized by intercalation of the heterobinuclear cation of the complex NiLa(fsaen)NO3 between the layers of montmorillonite clay and calcination at 500-degrees-C. The adsorption mechanism of the complex follows an exchange reaction involving up to 2 mmol of complex cations per g of clay. Further amounts of complex are adsorbed in sites other than exchange ones as shown by zeta-potential experiments. The IR spectra of the intercalated complex showed no major alterations of the complex during adsorption and a stabilization effect and enhancement of the parallel orientation of the clay plates. X-Ray diffraction (XRD) measurements at low angles showed that the pillared clay possesses an interlayer distance of 13.4 angstrom at 500-degrees-C. Its BET surface area reaches a maximum of 220 m2 g-1 at this temperature. The a(s) plots showed a maximum microporosity at less-than-or-equal-to 2 mmol g-1 Additional loading results in transformation to a mesoporous delaminated structure. X-Ray photoelectron spectra (XPS) of the composite materials showed that the ratios La/Si and Ni/Si are lower than those determined by chemical analysis, owing to the shielded environment of the LaNiO(x) pillars in the clay. The same method indicated that for a high degree of loading the aggregates seem to be of perovskite origin.
(EN)
