J.M. Domínguez

Study of pillar precursors [Ga(III)–Al(III), Ln(III)–Al(III), Zr(IV)] for hydrothermally stable pillared clays

Abstract The hydrolysis of mixed solutions of Al(III), Ga(III), Al(III), Ln(III) and Zr(IV) was studied by potentiometric, spectrophotometric and 27 Al - and 71 Ga -NMR techniques. For the Al–Ga system formation of GaAl12(OH)11+28 species seems more probable into the pH range 4≤pH≤5. Afterwards, the Al13(OH)7+32 species predominate in agreement with thermodynamic data obtained by SUPERQUAD program. Both tetrahedral GaIV and AlIV may coexist in solution, the interval being defined by potentiometric methods. For the Ln(III)–Al(III) systems 27 Al -and 139 La -NMR does not confirm the chemical interaction between the two species in solution, but the physicochemical properties of the La–Al/PILCS were different than Al/PILCS, suggesting a strong interaction in the solid state. Ce(III) and Ce(IV) ions do interact with Al(III) in solution, into the pH range 2.78 3.0.

Molybdenum and Tungsten carbides supported on Mesostructured MCM-41 material with polymeric carbon

Ni-Mo and Ni-W carbides phases supported on mesostructured MCM-41 with polymeric carbon were prepared in order to give structural stability to support. Surfaces as well as the structural properties of materials were studied. XRD and TEM analysis showed a similar structure before and after the treatment although geometrical and periodicity arrangements decrease lightly.

TRANSITION BIMETALLIC CARBIDES: SYNTHESIS AND CHARACTERIZATION

Two series of metal transition bimetallic carbides catalysts unsupported and supported on y-Al203 (Mo and W) from salts sources were prepared by the Volpe and Boudart modified method. The final structural and crystallographic properties were characterized by XRD, BET, TEM, TPD of NH3 techniques to observe the effect of synthesis conditions.The solids were used as a hydrotreating catalysts in the hydrodesulfurization of thiophene.

08-P-09-Study of mesoporous materials with ultra high surface area prepared from alternate surfacetants and silicate sources

Publisher Summary This chapter presents a study of mesoporous materials with ultra high surface area prepared from alternate surfactants and silicate sources. A comparison study on the synthesis of mesoporous materials from Triton X-100/Na-metasilicate and cetyltrimethylammonium bromide/ tetraethyl orthosilicate (CTAB/TEOS) is performed, and their textural and structural parameters are characterized by X-ray diffraction (XRD), N 2 adorption, and transmission electron microscopy (TEM). The CTAB/TEOS solids presented high surface mesopore areas, exceeding 1100 m 2 /g while the Triton X-100/Na-metasilicate presented areas from 1200 up to 1467 m 2 /g. The analysis of the textural data indicates that upon calcination, pore sintering occurs in the Triton/Na-metasilicate solids while it does not occur in the CTAB/TEOS system. This is probably because of the different packing effective factor of the surfactant molecules.