Selective hydrogenation of citral to unsaturated alcohols over mesoporous Pt/Ti-Al2O3 catalysts. Effect of the reduction temperature and of the Ge addition - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Molecular Catalysis A: Chemical Année : 2012

Selective hydrogenation of citral to unsaturated alcohols over mesoporous Pt/Ti-Al2O3 catalysts. Effect of the reduction temperature and of the Ge addition

Résumé

Pt/y%Ti-Al2O3 (y corresponding to the atomic percent of Ti in alumina, in the range 10-33%), and derived bimetallic Pt-Ge/10%Ti-Al2O3 nanocomposite catalysts were synthesized, characterized, and reduced either at 300 degrees C and 500 degrees C (this latter temperature being performed in order to generate strong metal-support interactions, i.e. a SMSI effect). The materials were characterized in detail with techniques including elemental analysis, X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and nitrogen physisorption to evaluate their structural and textural properties. Due to the templating approach used, well-defined mesopore structures with high surface areas and mesopore volumes are obtained for all materials. The SMSI effect, evaluated using a structure insensitive model reaction, i.e. the cyclohexane dehydrogenation, is observed to be more pronounced on the Pt/y%Ti-Al2O3 catalysts with y = 20 and 33% than on a Pt/TiO2 P25 (Degussa P25 titania) sample, showing the beneficial effect of Ti fine dispersion through incorporation in alumina matrix on the generated metal-support interaction. During citral hydrogenation reaction, the selectivity toward unsaturated alcohols (UA: nerol and geraniol) is related to Ti and/or Ge loadings on the nanocomposite, as well as reduction temperature. Both SMSI effect and Ge addition promote the UA selectivity leading to similar values than on Pt/TiO2 P25 sample. (C) 2011 Elsevier B.V. All rights reserved.

Dates et versions

hal-00683378 , version 1 (28-03-2012)

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Tchirioua Ekou, Aurelien Flura, Lynda Ekou, Catherine Especel, Sebastien Royer. Selective hydrogenation of citral to unsaturated alcohols over mesoporous Pt/Ti-Al2O3 catalysts. Effect of the reduction temperature and of the Ge addition. Journal of Molecular Catalysis A: Chemical, 2012, 353, pp.148-155. ⟨10.1016/j.molcata.2011.11.018⟩. ⟨hal-00683378⟩
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