References of "Pirard, Jean-Paul"
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See detailSol-gel preparation and characterisation of SnO2 powders employed as catalyst for phenol photodegradation
Benhebal, Hadj; Chaib, Messaoud; Léonard, Angélique ULg et al

in Scientia Iranica (2013), 20(6), 1891-1898

Crystallized pure SnO2 powders were prepared by the sol-gel process and were used as photocatalyst for the degradation of phenol under UV light at pH 6.5 and a temperature of 20°C. The physical properties ... [more ▼]

Crystallized pure SnO2 powders were prepared by the sol-gel process and were used as photocatalyst for the degradation of phenol under UV light at pH 6.5 and a temperature of 20°C. The physical properties of photocatalyst were characterized by X-ray diffraction, Scanning Electron Microscopy, nitrogen adsorption-desorption and Ultraviolet-visible diffuse reflectance spectroscopy. The influences of different operating variables such as the pH, the photocatalyst loading, the initial concentration of phenol, were studied to improve the efficiency of phenol degradation. [less ▲]

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See detailXPS structural characterization of Pd/SiO2 catalysts prepared by cogelation
Beketov, Gennadiy; Heinrichs, Benoît ULg; Pirard, Jean-Paul ULg et al

in Applied Surface Science (2013), 287

Nanostructured Pd/SiO2xerogel catalysts prepared via cogelation were characterized by X-ray photo-electron spectroscopy. The preparation route allowed highly porous silica particles to be formed alongwith ... [more ▼]

Nanostructured Pd/SiO2xerogel catalysts prepared via cogelation were characterized by X-ray photo-electron spectroscopy. The preparation route allowed highly porous silica particles to be formed alongwith embedded Pd nanocrystals. After heat-treating the catalysts in vacuum, Pd was found to be in themetallic state. To obtain information on the xerogel catalyst texture and, in particular, on the size of thesilica particles, a theoretical formalism was developed based on measuring the relative intensities of Pd 3ddoublet and the associated background tail due to inelastically scattered photoelectrons. The suggestedprocedure also involved the measurement of the background tails accompanying Si 2p and O 1s spectrallines as internal standards. Using the developed formalism, the size of the silica particles in the catalystsafter different treatments was evaluated and compared with TEM data. The results obtained indicate thatthe textural properties of the sol–gel catalysts start to develop already at the level of co-condensation ofalkoxides with the network-forming reagent. Calcination causes these properties to run to completion. [less ▲]

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See detailCatalytic layer for PEMFC based on carbon xerogels
Deschamps, Fabien ULg; Traina, Karl; Pirard, Jean-Paul ULg et al

in Proceedings of the Fundamentals and Development of Fuel cells 2013 conference (2013)

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See detailPropriétés physicochimiques et électrochimiques de catalyseurs Pt/xérogel de carbone synthétisés par la méthode de SEA multiple.
Zubiaur, Anthony ULg; Chatenet, M.; Maillard, F. et al

Conference (2012, October 01)

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See detailCarbon nanotube synthesis by CCVD process: kinetic study on a Ni-Mo/MgO catalyst
Douven, Sigrid ULg; Pirard, Sophie ULg; Chan, Fang-Yue et al

Poster (2012, October)

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See detailAdsorption du bleu de méthylène sur des xérogels de carbone activés
Páez Martínez, Carlos ULg; Contreras, Soledad; Léonard, Angélique ULg et al

Poster (2012, October)

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See detailSynthèse de MWNT dans un réacteur continu incliné rotatif à lit mobile par procédé CCVD
Douven, Sigrid ULg; Pirard, Sophie ULg; Chan, Fang-Yue et al

Conference (2012, October)

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See detailUse of new surface active carbohydrate esters for the synthesis of polyhipes in supercritical CO2
Boyère, Cédric ULg; Favrelle, Audrey; Grignard, Bruno ULg et al

Poster (2012, September 10)

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See detailSynthesis of microsphere-loaded porous polymers by combining emulsion and dispersion polymerisations in supercritical carbon dioxide
Boyère, Cédric ULg; Léonard, Alexandre ULg; Grignard, Bruno ULg et al

in Chemical Communications (2012), 48(67), 8356-8358

Highly porous materials were produced by acrylamide polymerisation templated by supercritical CO2-in-water emulsions using new fluorinated glycosurfactants. Properties of the resulting polymer scaffolds ... [more ▼]

Highly porous materials were produced by acrylamide polymerisation templated by supercritical CO2-in-water emulsions using new fluorinated glycosurfactants. Properties of the resulting polymer scaffolds were tuned by performing dispersion polymerisations within their cavities filled with supercritical CO2. [less ▲]

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See detailResorcinol-formaldehyde carbon xerogels as lithium-ion battery anode materials: influence of porosity on capacity and cycling behaviour
Piedboeuf, Marie-Laure ULg; Léonard, Alexandre ULg; Khomenko, Volodymyr et al

Poster (2012, July 05)

Carbon xerogels are promising candidates in the development of new high performance C-based anode materials for Li-ion batteries. Indeed, their specific capacities widely exceed that of conventional ... [more ▼]

Carbon xerogels are promising candidates in the development of new high performance C-based anode materials for Li-ion batteries. Indeed, their specific capacities widely exceed that of conventional graphitic structures, and they can be intercalated/deintercalated in a low-cost electrolyte based on propylene carbonate (PC), which has an excellent conductivity at low temperatures. In addition, such carbonaceous materials show very small changes of volume during the charge/discharge, providing a long cycle life of such an anode. Nevertheless, hard carbons also exhibit quite high irreversible capacity losses due to their intrinsic high microporosity and, compared to graphite, a poor rate performance related to slow diffusion of Li in the internal structure[1]. To reduce these disadvantages, the structural and textural characteristics need to be carefully controlled. Porous carbon xerogels can easily be prepared from resorcinol-formaldehyde aqueous mixtures, which are polymerized, dried and pyrolysed. The porosity of these xerogels is mainly governed by the pH of the precursor solution as well as by the drying procedure. Globally, these materials are composed of microporous nodules delimiting meso- or macroporous voids, the size of which is adjusted via the synthesis pH. Too a high microporosity can induce considerable irreversible capacity losses and too small mesopores may hinder the proper chemical diffusion of lithium ions within a bulk electrode material. The latter is often a rate-limiting step and optimized transport pathways could be provided by creating large mesopores or even macropores within the microporous carbon [3]. Here we report on the preliminary electrochemical characterization of porous carbon xerogels prepared by vacuum drying procedure. By adjusting the pH of the precursor solution, the materials obtained develop low to high values of specific surface areas and exhibit homogeneous pore sizes that range from several microns to several nanometers. The electrochemical performance of these materials as electrode compounds was tested by galvanostatic charge-discharge of 16-mm disc electrodes assembled in CR2016 coin cells or of 13-mm disc electrodes in home-made Swagelok-type cells. The first results show that all the samples show quite a high irreversible capacity during the first cycle; this irreversible capacity is proportional to the specific surface area. Its value nevertheless remains quite low for the low-surface area macroporous sample. The latter also shows the best reversible capacity after the second cycle, with values approaching that of commonly used graphite. For example, when cycled at a rate of C/20 for 10 cycles, this sample showed a capacity of 320 mAh/g; the value was kept at 200 mAh/g when increasing the rate up to C/5. The long-term cycling performance was investigated by cycling the anodes at C/20 and C/5. Again, the macroporous sample behaves best, with superior capacity retention and invariable discharge capacity of ~175 mAh/g after more than 100 cycles. The electrochemical properties of carbon xerogels was evaluated in the conditions which are used typically for graphite (cycles in the potentials range from 0.003 to 1.5 V vs. Li+/Li). A higher reversible capacity of 400 mAh/g could be obtained for the macroporous sample using a discharge with plating of Li as described in [4], but this method could not be accepted in the case of Lithium-ion batteries. These first results show that carbon xerogels are very promising candidates as anode materials for Li batteries, providing the textural characteristics are carefully controlled. The ongoing work is dealing with the establishment of possible relationships between textural features and electrochemical performance in order to shed light on the requirements that will dictate the best synthesis procedures. References: [1] T. Tran, B. Yebka, X. Song, G. Nazri, K. Kinoshita and D. Curtis, J. Power Sources, 85, 269, 2000. [2] N. Job, A. Théry, R. Pirard, J. Marien, L. Kocon, J.-N. Rouzaud, F. Béguin and J.-P. Pirard, Carbon 43, 2481, 2005. [3] F. Cheng, Z. Tao, J. Liang, and J. Chen, Chem. Mater., 20, 667, 2008. [4] W. Xing, J. S. Xue, J.R. Dahn, J. Electrochem. Soc, 143, 3046, 1996. [less ▲]

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See detailSynthesis and characterization of porous carbon xerogels and ordered mesoporous carbons for anode materials in Li-based batteries
Léonard, Alexandre ULg; Pirard, Jean-Paul ULg; Job, Nathalie ULg

in Fagadar-Cosma, Eugenia (Ed.) Insights into novel solid materials, their recyclability and integration into Li polymer batteries for EVs. Future research directions in this field.:Book of abstracts (2012, July 04)

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See detailResorcinol-formaldehyde carbon xerogels as lithium-ion battery anode materials: influence of porosity on capacity and cycling behaviour
Léonard, Alexandre ULg; Piedboeuf, Marie-Laure ULg; Khomenko, Volodymyr et al

in Fagadar-Cosma, Eugenia (Ed.) Insights into novel solid materials, their recyclability and integration into Li polymer batteries for EVs. Future research directions in this field.:Book of abstracts (2012, July)

Detailed reference viewed: 26 (14 ULg)