References of "Alié, Christelle"
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See detailEffects of additives and solvents on the gel formation rate and on the texture of P- and Si-doped TiO2 materials
Bodson, Céline ULg; Lambert, Stéphanie ULg; Alié, Christelle ULg et al

in Microporous & Mesoporous Materials (2010), 134

Organic/inorganic hybrid TiO2 xerogels have been synthesized from titanium tetraisopropoxide and an organosilylated or organophosphorylated additive either in 2-methoxyethanol or isopropanol. The ... [more ▼]

Organic/inorganic hybrid TiO2 xerogels have been synthesized from titanium tetraisopropoxide and an organosilylated or organophosphorylated additive either in 2-methoxyethanol or isopropanol. The mechanisms of formation of the gels have been studied before gelation by liquid NMR spectroscopy and connected to their structure after drying analyzed by Raman spectroscopy, solid state NMR and N2 adsorption/desorption. The effects of the additives and solvents on the gel formation rate and on the texture of the xerogel have been addressed. [less ▲]

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See detailAg-and SiO2-doped porous TiO2 with enhanced thermal stability
Braconnier, Benoît ULg; Páez Martínez, Carlos ULg; Lambert, Stéphanie ULg et al

in Microporous & Mesoporous Materials (2009), 122

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See detailSynthesis of Ag/TiO2 hybrid photocatalysts by sol-gel process with new P-alkoxide functionalized ligands
Lambert, Stéphanie ULg; Bied, Catherine; Bodson, Céline et al

Poster (2009)

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See detailDécomposition photocatalytique de polluants et de micro-organismes dans l'eau
Heinrichs, Benoît ULg; Pirard, Jean-Paul ULg; Lambert, Stéphanie ULg et al

E-print/Working paper (2008)

Dans le cadre de la réutilisation des eaux usées et de l’accès limité à l’eau potable dans certaines régions du globe, de nouvelles techniques de désinfection nécessitant de faibles consommations ... [more ▼]

Dans le cadre de la réutilisation des eaux usées et de l’accès limité à l’eau potable dans certaines régions du globe, de nouvelles techniques de désinfection nécessitant de faibles consommations d’énergie sont étudiées. Cette eau n’est pas toujours potable et contient des polluants qui induisent des mutations génétiques pouvant conduire au développement de cancers ou encore des micro-organismes pathogènes causant des maladies graves. Depuis la découverte des propriétés de photodégradation oxydante du dioxyde de titane (TiO2), la photocatalyse hétérogène est utilisée pour l’élimination des polluants environnementaux et des micro-organismes. [less ▲]

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See detailPhotodegradation of bacteria with TiO2 produced by sol-gel method
Tasseroul, Ludivine ULg; Pàez Martinez, Carlos ULg; Braconnier, Benoît et al

Poster (2007)

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See detailMethods for the preparation of bimetallic xerogel catalysts designed for chlorinated wastes processing
Lambert, Stéphanie ULg; Ferauche, Fabrice; Heinrichs, Benoît ULg et al

in Journal of Non-Crystalline Solids (2006), 352(26-27), 2751-2762

The aim of this work is to simplify and generalize the synthesis procedure of bimetallic supported catalysts by sol-gel process. For Pd-Ag/SiO2, co-gelled xerogels catalysts a number of synthesis ... [more ▼]

The aim of this work is to simplify and generalize the synthesis procedure of bimetallic supported catalysts by sol-gel process. For Pd-Ag/SiO2, co-gelled xerogels catalysts a number of synthesis procedures were compared: use of one or two specific alkoxides able to form a chelate with palladium and/or silver cations, reagent mixing in one or two steps, use of industrial grade chemicals instead of laboratory grade chemicals. The catalysts obtained are quite similar: same metal dispersion, same tailored morphology, same localization and accessibility of Pd-Ag alloy nanoparticles inside microporous silica, same activity and selectivity for hydrodechlorination of 1,2-dichloroethane into ethylene. For catalyst production at large scale the synthesis can be achieved in one step with 3-(2-aminoethyl)aminopropyltrimethoxysilane of industrial grade as chelating alkoxide, tetraethylorthosilicate (TEOS) of industrial grade and ethanol denatured with diethyl phthalate. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailMultigram scale synthesis and characterization of low-density silica xerogels
Alié, Christelle ULg; Tcherkassova, Natalia ULg; Ferauche, Fabrice et al

in Journal of Non-Crystalline Solids (2006), 352(26-27), 2763-2771

The synthesis of silica with preserved porosity and tailored morphology by sol-gel process can be achieved by hybrid organic-inorganic synthesis: a modified alkoxide, viz. 3-(2-aminoethylamino ... [more ▼]

The synthesis of silica with preserved porosity and tailored morphology by sol-gel process can be achieved by hybrid organic-inorganic synthesis: a modified alkoxide, viz. 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS), is introduced during the base catalysed synthesis with TEOS as main silica precursor. Additives with methoxy groups induce a nucleation mechanism because of their higher reactivity compared to main reagents with ethoxy groups. The nucleation model presented in previous papers was refined by taking into account the porosity of the particles and calculating the number of additive molecules by nucleus for each value of the ratio of additive/main reagent. The extrapolation of the synthesis process to semi-industrial scale goes through the replacement of laboratory grade reagents by industrial grade reagents and the scaling up to the production of higher quantities. At each of these two steps, the morphology and porosity of the samples has been compared to those of laboratory grade samples. It was shown that the texture and particle size has quasi totally been preserved. (c) 2006 Elsevier B.V. All rights reserved. [less ▲]

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See detailPd-Ag/SiO2 xerogel catalyst forming by impregnation on alumina foams
Alié, Christelle ULg; Ferauche, Fabrice; Léonard, Angélique ULg et al

in Chemical Engineering Journal (2006), 117(1), 13-22

A Pd-Ag/SiO2 xerogel catalyst prepared in one step by sol-gel process has been entrapped in cylindrical porous alumina foams of three different pore sizes in order to shape the catalyst under the ... [more ▼]

A Pd-Ag/SiO2 xerogel catalyst prepared in one step by sol-gel process has been entrapped in cylindrical porous alumina foams of three different pore sizes in order to shape the catalyst under the appropriate form with suitable mechanical resistance to be used in an industrial fixed bed reactor. After drying, calcination and reduction, the Pd-Ag/SiO2 xerogel catalyst pellets are immobilized inside the open porosity of the alumina foam. The localization of the xerogel catalyst in the alumina foams has been studied by X-ray tomography. The three-dimensional porous structure was reconstructed from the consecutive cross-sections obtained by this technique. This method shows that the Pd-Ag/SiO2 xerogel catalyst is uniformly dispersed inside the porosity of the alumina foams. Activity and selectivity of Pd-Ag/SiO2 xerogel catalyst reference or catalyst entrapped in alumina foams have been studied for selective hydrodechlorination of 1,2-dichloroethane into ethylene. The specific reaction rate obtained with catalyst entrapped in alumina foams is smaller than the one obtained from corresponding catalyst powders. The catalytic activity decrease observed for Pd-Ag/SiO2 xerogel catalyst entrapped in porous alumina foams most probably arises from diffusional limitations inside the porous texture of the alumina foams. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailLarge-scale synthesis and shaping of xerogel catalysts
Alié, Christelle ULg; Ferauche, Fabrice; Tcherkassova, Natalia et al

Poster (2006)

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See detailLarge-scale synthesis and forming of xerogel catalysts
Alié, Christelle ULg; Ferauche, Fabrice; Tcherkassova, Natalia et al

in Studies in Surface Science and Catalysis (2006), 162

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See detailNon intrusive mercury porosimetry: Pyrolysis of resorcinol-formaldehyde xerogels
Job, Nathalie ULg; Pirard, René ULg; Pirard, Jean-Paul ULg et al

in Particle & Particle Systems Characterization (2006), 23(1), 72-81

When submitted to mercury porosimetry, some materials are penetrated by mercury whereas others, among the most porous, are densified by the isostatic pressure. Notably, this is the case for materials ... [more ▼]

When submitted to mercury porosimetry, some materials are penetrated by mercury whereas others, among the most porous, are densified by the isostatic pressure. Notably, this is the case for materials whose structure is made of particles aggregated into filament-like clusters that are interconnected in a 3-D array. Indeed, that kind of material undergoes a volume variation due to hierarchical pore collapse. In the case of intrusion, the mercury porosimetry data are classically analyzed by the Washburn equation. In the case of hierarchical pore collapse, data can be correctly analyzed by the collapse model equation. Using an equation that does not correspond to the mechanism leads to large errors in the pore size distribution. Thus, an accurate data analysis requires prior determination of the mechanism leading to the volume variation recorded as a function of the pressure. The present work particularly examines the complex and unusual behavior of partially pyrolyzed resorcinol-formaldehyde gels when submitted to mercury porosimetry. The unusual behavior encountered complicates the mechanism identification and, therefore, the equation selection. However, the major part of the volume distribution as a function of the pore size can be determined with a good accuracy. [less ▲]

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See detailFormation and structural characteristics of Pd-Ag/SiO2 and Pd-Cu/SiO2 catalysts synthesized by cogelation
Lambert, Stéphanie ULg; Gommes, Cédric ULg; Alié, Christelle ULg et al

in Journal of Non-Crystalline Solids (2005), 351(52-54), 3839-3853

Pd-Ag/SiO2 and Pd-Cu/SiO2 xerogel catalysts have been synthesized by cogelation of tetraethoxysilane (TEOS) and chelates of either Pd and Ag or Pd and Cu with 3-(2-aminoethylamino)propyltrimethoxysilane ... [more ▼]

Pd-Ag/SiO2 and Pd-Cu/SiO2 xerogel catalysts have been synthesized by cogelation of tetraethoxysilane (TEOS) and chelates of either Pd and Ag or Pd and Cu with 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS). After an extensive study of the influences of synthesis operating variables over structural characteristics of gels, highly dispersed bimetallic Pd-Ag/SiO2 and Pd-Cu/SiO2 xerogel catalysts were obtained. These samples are then composed of completely accessible Pd-Ag and Pd-Cu alloy crystallites with sizes of 2-3.5 nm located inside silica particles exhibiting a monodisperse microporous distribution. It appears also that the metal complex acts as a nucleation agent in the formation of silica particles. (c) 2005 Elsevier B.V. All rights reserved. [less ▲]

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See detailPreparation and characterization of xerogel catalyst microspheres
Alié, Christelle ULg; Ferauche, Fabrice; Heinrichs, Benoît ULg et al

in Journal of Non-Crystalline Solids (2004), 350

For easier handling and use in fixed bed reactors, Pd-Ag/SiO2 aerogel-like xerogel catalysts were shaped into microspheres using the microencapsulation process developed by BRACE GmbH. Before the bead ... [more ▼]

For easier handling and use in fixed bed reactors, Pd-Ag/SiO2 aerogel-like xerogel catalysts were shaped into microspheres using the microencapsulation process developed by BRACE GmbH. Before the bead production process, the xerogel catalyst was ground in water and mixed with ethylene glycol and sodium alginate, the latter of which is the gelation agent. The beads were formed at a vibrating nozzle and solidified during their fall in a water tank containing calcium ions, which induce cross-linking of the alginate and consequent bead hardening. Preliminary work was done using a syringe instead of the material-consuming BRACE unit. The beads were made from a suspension of dried only, dried and calcined, or dried, calcined, and reduced catalyst. The textural properties of the beads were analyzed by nitrogen adsorption-desorption isotherms and mercury porosimetry; and bead catalytic activity was tested for selective hydrodechlorination of 1,2-dichloroethane. The beads made from a suspension of dried catalyst appear to have properties the closest to that of the xerogel reference catalyst. Porosity and surface area are maintained at their level before bead formation. However conversion of 1,2-dichloroethane decreases after the production process, possibly due to poisoning by calcium ions. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailStudy of textural properties and nucleation phenomenon in Pd/SiO2, Ag/SiO2 and Cu/SiO2 cogelled xerogel catalysts
Lambert, Stéphanie ULg; Alié, Christelle ULg; Pirard, Jean-Paul ULg et al

in Journal of Non-Crystalline Solids (2004), 342(1-3), 70-81

Pd/SiO2, Ag/SiO2 and CU/SiO2 xerogel catalysts have been synthesized by cogelation of tetraethoxysilane (TEOS) and chelates of Pd, Ag and Cu with 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS). The ... [more ▼]

Pd/SiO2, Ag/SiO2 and CU/SiO2 xerogel catalysts have been synthesized by cogelation of tetraethoxysilane (TEOS) and chelates of Pd, Ag and Cu with 3-(2-aminoethylamino)propyltrimethoxysilane (EDAS). The resulting materials are composed of completely accessible metallic crystallites with a diameter of about 3 nm, located inside silica particles exhibiting a monodisperse microporous distribution centered on a pore width of about 0.8 nm. Voids between silica particles and between aggregates of silica particles constitute the material meso- and macroporous texture. The EDAS/TEOS ratio is the main operating variable to tailor the material morphology. When the EDAS/TEOS ratio decreases, metallic particle size decreases, whereas silica particle size increases. Thus the meso- and macropores between silica particles are larger. So the total pore volume can reach 5 cm(3)/g when the EDAS/TEOS ratio decreases. The remarkable morphology of these materials can be explained by the rule in which the EDAS metal complex acts as a nucleation agent in the formation of silica particles. A nucleation mechanism by EDAS-metal complex based on mass equations and the nuclei formation kinetics allows fitting the entire results. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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