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1. Selective Deposition of Palladium Nanoparticles inside the Bimodal Porosity of β-SiC Investigated by Electron Tomography

Author

Charlotte Pham, Adrien Deneuve, Cuong Pham-Huu, Patrick Nguyen, Izabela Janowska, Ileana Florea, Lucian Roiban, Ovidiu Ersen, and Matthieu Houllé

Subjects
Materials science, business.industry, Nanotechnology, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, General Energy, Electron tomography, chemistry, Specific surface area, visual_art, visual_art.visual_art_medium, Silicon carbide, Microelectronics, Nanometre, Ceramic, Physical and Theoretical Chemistry, Porosity, Dispersion (chemistry), business
Abstract

Silicon carbide (SiC) is a ceramic material that has received intensive consideration during the past decade owing to its attractive properties and the diversity of its applications, ranging from microelectronics to catalysis. In particular, new β-SiC materials with high specific surface area are of great interest to the area of industrial catalysis. The aim of the present article is to report the direct visualization of the porous network of β-SiC in a nanometer range using the ability of electron tomography (ET) but also to determine the precise localization of active phases with respect to the porosity of this support. Focus is set on the use of ET to get more insight about the filling mode during sample preparation and, finally, the dispersion and accessibility of the active phase. Thus, an intensive study of the impact of the impregnation solvents on the active phase localization has also been carried out and selective deposition of the active phase within the porous network of SiC is evidenced. In a...

Published
2009

2. Mechanical enhancement of C/C composites via the formation of a machinable carbon nanofiber interphase

Author

Adrien Deneuve, Matthieu Houllé, Julien Amadou, Cuong Pham-Huu, and Dominique Begin

Subjects
Materials science, Carbonization, Carbon nanofiber, Thermal decomposition, chemistry.chemical_element, General Chemistry, chemistry, Nanofiber, General Materials Science, Interphase, Pyrolytic carbon, Composite material, Pyrolysis, Carbon
Abstract

C/C composites with improved mechanical strength were synthesized using a filler constituted by a carbon felt covered with catalytically grown carbon nanofibers (CNFs) and a carbonaceous matrix generated by the pyrolysis of a phenolic resin. First, the synthesis method of the filler allows the homogeneous deposition and anchorage of CNFs on the host microfilaments at a rapid densification rate. Carbon nanofibers grown this way lead to the formation of numerous micro- and nanobridges between the microfilaments, conferring a significant improvement of the mechanical resistance of the CNF/C system allowing one to tailor its dimensions and shape. Thus, further fabrication of C/C composites can be achieved: the CNF/microfilament structure was infiltrated with a phenolic resin and carbonized at 650 °C to generate a carbonaceous matrix by thermal decomposition. Similar experiments on the microfilaments carried out at the same synthesis time, without catalyst and at higher reaction temperatures led to the deposition of a pyrolytic carbon sheath and to poor mechanical enhancements. This clearly indicates the advantage of using CNF growth as an efficient densification process before infiltration. Such C/C composites exhibit high-quality bonding between the two carbon phases, the matrix and the CNF/microfilament filler, via the formation of a considerable amount of CNF interphase.

Published
2008

3. Nitrogen-Doped Carbon Nanotubes as a Highly Active Metal-Free Catalyst for Selective Oxidation

Author

Kambiz Chizari, Ovidiu Ersen, Dominique Begin, Cuong Pham-Huu, Adrien Deneuve, David Edouard, Izabela Janowska, Ileana Florea, Yu Liu, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Beihang University (BUAA), Laboratoire d'automatique et de génie des procédés (LAGEP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS), Department of Organic Chemistry, Łódź University of Technology, Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Nitrogen, General Chemical Engineering, Catalyst support, Inorganic chemistry, Oxide, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, Heterogeneous catalysis, 01 natural sciences, 7. Clean energy, Catalyst poisoning, Catalysis, Substrate Specificity, law.invention, chemistry.chemical_compound, [SPI]Engineering Sciences [physics], [CHIM.GENI]Chemical Sciences/Chemical engineering, law, Environmental Chemistry, [CHIM]Chemical Sciences, General Materials Science, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Hydrogen Sulfide, ComputingMilieux_MISCELLANEOUS, Nanotubes, Carbon, Temperature, 021001 nanoscience & nanotechnology, 0104 chemical sciences, General Energy, chemistry, Carbon nanotube supported catalyst, 0210 nano-technology, Oxidation-Reduction, Sulfur, Space velocity
Abstract

Catalytic reactions are generally carried out on supported metals or oxides, which act as an active phase and require impregnation and thermal treatment steps. During tests, the metal or oxide nanoparticles could be further sintered, which would induces deactivation. Direct incorporation of the active phase into the matrix of a support could be an elegant alternative to prevent catalyst deactivation. Here, we report that nitrogen-doped carbon nanotubes (N-CNTs) can be efficiently employed as a metal-free catalyst for oxidative reactions that allow the selective transformation of the harmful, gaseous H(2)S into solid sulfur. The catalyst exhibits a high stability during the test at high space velocity. The macroscopic shaping of the catalyst on the silicon carbide foam also increases its catalytic activity by improving the contact between the reactants and the catalyst. Such macroscopic shaping allows the avoidance of problems linked with transport and handling of nanoscopic materials and also reduces the pressure drop across the catalyst bed to a large extent.

Published
2012

4. Analytical electron tomography mapping of the SiC pore oxidation at the nanoscale

Author

Ileana Florea, Adrien Deneuve, Matthieu Houllé, Izabela Janowska, Cuong Pham-Huu, Charles Hirlimann, Charlotte Pham, Lucian Roiban, Patrick Nguyen, and Ovidiu Ersen

Subjects
Materials science, Catalyst support, Carbon Compounds, Inorganic, Photoelectron Spectroscopy, Silicon Compounds, Nanotechnology, Catalysis, chemistry.chemical_compound, Chemical engineering, chemistry, Electron tomography, Specific surface area, visual_art, visual_art.visual_art_medium, Silicon carbide, Nanoparticles, General Materials Science, Wetting, Ceramic, Porosity, Nanoscopic scale, Oxidation-Reduction
Abstract

Silicon carbide is a ceramic material that has been widely studied because of its potential applications, ranging from electronics to heterogeneous catalysis. Recently, a new type of SiC materials with a medium specific surface area and thermal conductivity, called β-SiC, has attracted overgrowing interest as a new class of catalyst support in several catalytic reactions. A primary electron tomography study, performed in usual mode, has revealed a dual surface structure defined by two types of porosities made of networks of connected channels with sizes larger than 50 nm and ink-bottled pores with sizes spanning from 4 to 50 nm. Depending on the solvent nature, metal nanoparticles could be selectively deposited inside one of the two porosities, a fact that illustrates a selective wetting titration of the two types of surfaces by different liquids. The explaining hypothesis that has been put forward was that this selectivity against solvents is related to the pore surface oxidation degree of the two types of pores. A new technique of analytical electron tomography, where the series of projections used to reconstruct the volume of an object is recorded in energy filtered mode (EFTEM), has been implemented to map the pore oxidation state and to correlate it with the morphology and the accessibility of the porous network. Applied, for the first time, at a nanoscale resolution, this technique allowed us to obtain 3D elemental maps of different elements present in the analysed porous grains, in particular oxygen; we found thus that the interconnected channel pores are more rapidly oxidized than the ink-bottled ones. Alternatively, our study highlights the great interest of this method that opens the way for obtaining precise information on the chemical composition of a 3D surface at a nanometer scale.

Published
2010

5. Catalytic growth of silicon carbide composite with nanoscopic properties and enhanced oxidative resistance as catalyst support

Author

Ileana Florea, Adrien Deneuve, Patrick Nguyen, Marc-Jacques Ledoux, Charlotte Pham, Ovidiu Ersen, David Edouard, Cuong Pham-Huu, Dominique Begin, Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'automatique et de génie des procédés (LAGEP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS), Bureau d'Économie Théorique et Appliquée (BETA), Université de Lorraine (UL)-Université de Strasbourg (UNISTRA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), and Institut National de la Recherche Agronomique (INRA)-Université de Strasbourg (UNISTRA)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Catalyst support, Composite number, 02 engineering and technology, 010402 general chemistry, Heterogeneous catalysis, 7. Clean energy, 01 natural sciences, Catalysis, Methane, Steam reforming, chemistry.chemical_compound, [SPI]Engineering Sciences [physics], [CHIM.GENI]Chemical Sciences/Chemical engineering, stomatognathic system, Silicon carbide, [CHIM]Chemical Sciences, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Nanoscopic scale, ComputingMilieux_MISCELLANEOUS, Process Chemistry and Technology, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Chemical engineering, 0210 nano-technology
Abstract

Resistance to oxidation is a major point in catalysis processes when it comes to the properties of catalyst supports that are exposed to harsh conditions such as high temperature and non-negligible concentration of oxidative agents. Indeed, consistent oxidation often leads to the destruction of the support and loss of the catalyst material. Silicon carbide (SiC) has already proved to be very resistant to oxidation below 700 °C, but some applications (such as steam methane reforming) require higher oxidative resistance. In this work, we report the synthesis of a new SiC composite made of a β-SiC host structure covered with SiC nanofibres which exhibits a significant improved oxidative resistance. Such increase of the oxidative resistance was explained by a defect-site inhibition mechanism induced by the presence of SiC nanofibres that was checked with and without the presence of an oxidative catalyst.

Published
2010

6. 1D SiC decoration of SiC macroscopic shapes for filtration devices

Author

David Edouard, Gauthier Winé, Adrien Deneuve, Patrick Nguyen, Charlotte Pham, Svetlana Ivanova, Ovidiu Ersen, Cuong Pham-Huu, Estelle Vanhaecke, North-Eastern Federal University, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Laboratoire d'automatique et de génie des procédés (LAGEP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École Supérieure Chimie Physique Électronique de Lyon-Centre National de la Recherche Scientifique (CNRS), Bureau d'Économie Théorique et Appliquée (BETA), Institut National de la Recherche Agronomique (INRA)-Université de Strasbourg (UNISTRA)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Norwegian University of Science and Technology [Trondheim] (NTNU), Norwegian University of Science and Technology (NTNU), Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse (LMSPC), Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), Université de Lorraine (UL), Université de Strasbourg (UNISTRA), Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), The present work is financially supported by Sicat SA Otterswiller, France. Dr Th. Dintzer (LMSPC) is gratefully acknowledged for performing SEM experiments. P. Bernhardt (LMSPC) is also gratefully acknowledged for performing XPS analysis. Dr S. Rigolet and Dr Cl. Marichal (LCPM) are gratefully acknowledged for performing 29Si NMR analysis and for helpful discussion., Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and Université de Lorraine (UL)-Université de Strasbourg (UNISTRA)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Composite number, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, [SPI]Engineering Sciences [physics], Thermal conductivity, [CHIM.GENI]Chemical Sciences/Chemical engineering, Specific surface area, Materials Chemistry, Silicon carbide, [CHIM]Chemical Sciences, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Ceramic, Composite material, Porosity, Nanoscopic scale, ComputingMilieux_MISCELLANEOUS, General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, visual_art, Nanofiber, visual_art.visual_art_medium, 0210 nano-technology
Abstract

International audience; The synthesis of a hierarchical support, constituted of a network of SiC nanofibers deposited on a SiC foam host resulting in a ceramic material with a controlled macroscopic shape and associated high specific surface area superior to 50 m2 g1, has been reported for the first time. The new composite combines the nanoscopic properties of the SiC nanofibers’ network and controlled macroscopic shape and open porosity, typical of a SiC foam structure. The introduction of the nanostructures onto the host material allows a dramatic increase in the effective surface area which is extremely useful for the chosen field of application. This new type of material has been efficiently employed as a diesel particulate filter at high space velocity and without a detrimental pressure drop. In addition, the combination of such a hierarchical structure with high thermal conductivity could give rise to unexpected results in the field of heterogeneous catalysis where the mass and heat transport limitations still need to be improved

Published
2008

7. Densification de composites carbonés par SPS : utilisation de nanofibres de carbone comme agent liant

Author

Julien Amadou, Adrien Deneuve, Claude Estournès, Matthieu Houllé, Cuong Pham-Huu, Marc-Jacques Ledoux, Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université Louis Pasteur-Strasbourg I - ULP (FRANCE), and Centre National de la Recherche Scientifique - CNRS (FRANCE)

Subjects
renforcement mécanique, Matériaux, nanofibres de carbone, General Materials Science, SPS, CVD, composites
Abstract

Des composites à base de carbone présentant une tenue mécanique élevée et de faibles masses volumiques peuvent être élaborés par densification SPS (Spark Plasma Sintering). Ces composites sont réalisés en deux étapes : un précurseur C/C est synthétisé par croissance catalytique CVD de nanofibres de carbone (NFCs) sur une préforme de carbone (feutre ou tissu de graphite), puis le composite obtenu est soumis à un traitement de densification par SPS (frittage à 1750 ◦C sous pression de plusieurs dizaines de kN). La réaction CVD utilise des nanoparticules de métaux de transition comme catalyseurs et de l’éthane (C2H6) comme source de carbone. Cette voie de synthèse permet de conserver la mise en forme macroscopique et de rigidifier la structure du précurseur par le biais des nombreuses jonctions créées pendant la formation des NFCs. Une préforme composite C/C est ainsi obtenue et découpée en pastilles pour subir le traitement SPS. Le frittage peut être précédé d’une étape d’infiltration de résine phénolique afin de réaliser des composites C/C/C : cette étape permet de densifier les composites en adjoignant une matrice de carbone par la décomposition de la résine, ce qui favorise la cohésion de l’ensemble. La présence d’éléments de taille nanoscopique permet d’un côté d’améliorer la résistance mécanique en augmentant le transfert de charge, et d’un autre côté de faciliter le frittage et l’infiltration de la résine dans le composite.

Published
2007

8. 1D SiC decoration of SiC macroscopic shapes for filtration devices.

Author

Estelle Vanhaecke, Svetlana Ivanova, Adrien Deneuve, Ovidiu Ersen, David Edouard, Gauthier Winé, Patrick Nguyen, Charlotte Pham, and Cuong Pham-Huu

Abstract

The synthesis of a hierarchical support, constituted of a network of SiC nanofibers deposited on a SiC foam host resulting in a ceramic material with a controlled macroscopic shape and associated high specific surface area superior to 50 m2 g−1, has been reported for the first time. The new composite combines the nanoscopic properties of the SiC nanofibers’ network and controlled macroscopic shape and open porosity, typical of a SiC foam structure. The introduction of the nanostructures onto the host material allows a dramatic increase in the effective surface area which is extremely useful for the chosen field of application. This new type of material has been efficiently employed as a diesel particulate filter at high space velocity and without a detrimental pressure drop. In addition, the combination of such a hierarchical structure with high thermal conductivity could give rise to unexpected results in the field of heterogeneous catalysis where the mass and heat transport limitations still need to be improved. [ABSTRACT FROM AUTHOR]

Published
2008
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