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Article Dans Une Revue Microporous and Mesoporous Materials Année : 2008

Tailor-made morphologies for Pd/SiO2 catalysts through sol–gel process with various silylated ligands

Résumé

With the aim of obtaining highly dispersed, immobilized and accessible catalytically active palladium nanoparticles in a silica support with a tailored morphology, a sol–gel cogelation method is developed. Pd/SiO2 catalysts are synthesized in ethanol by concomitant hydrolysis and condensation, i.e. cogelation, of a Pd2+[L–X–Si(OR)3]n complex with Si(OC2H5)4 (TEOS) as network-forming reagent followed by calcinations in air and by reductions of the resulting xerogel catalysts in hydrogen. By varying the nature of L, X and R in the Pd2+ complex, the purpose of the present work is to determine the influence of the nature of the L–X–Si(OR)3 ligand on textural properties of silica and on palladium dispersion in Pd/SiO2 catalysts. By changing the molecular weight of L–X– and thus its bulkiness of L and X, it is observed that with bulkier silylated ligand, the textural properties of resulting gels are strongly modified from micro- and macroporous materials to very highly micro- and mesoporous materials. In the latter ones, the size of silica particles is smaller and their void fraction is very high. In such a case, palladium particles are not trapped inside silica particles and are then able to migrate and to sinter. The Pd/SiO2 xerogel catalysts were evaluated in the hydrodechlorination of 1,2-dichloroethane.

Dates et versions

hal-00315987 , version 1 (02-09-2008)

Identifiants

Citer

Stéphanie Lambert, Kim Yen Tran, Guilhem Arrachart, Francis Noville, Catherine Henrist, et al.. Tailor-made morphologies for Pd/SiO2 catalysts through sol–gel process with various silylated ligands. Microporous and Mesoporous Materials, 2008, 115, pp.609-617. ⟨10.1016/j.micromeso.2008.03.003⟩. ⟨hal-00315987⟩
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