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1. Physical and Chemical Activation of Graphene-Derived Porous Nanomaterials for Post-Combustion Carbon Dioxide Capture

Author

Rabita Mohd Firdaus, Alexandre Desforges, Mélanie Emo, Abdul Rahman Mohamed, and Brigitte Vigolo

Subjects
graphene oxide, activation, porosity, adsorption, carbon dioxide, Chemistry, QD1-999
Abstract

Activation is commonly used to improve the surface and porosity of different kinds of carbon nanomaterials: activated carbon, carbon nanotubes, graphene, and carbon black. In this study, both physical and chemical activations are applied to graphene oxide by using CO2 and KOH-based approaches, respectively. The structural and the chemical properties of the prepared activated graphene are deeply characterized by means of scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry and nitrogen adsorption. Temperature activation is shown to be a key parameter leading to enhanced CO2 adsorption capacity of the graphene oxide-based materials. The specific surface area is increased from 219.3 m2 g−1 for starting graphene oxide to 762.5 and 1060.5 m2 g−1 after physical and chemical activation, respectively. The performance of CO2 adsorption is gradually enhanced with the activation temperature for both approaches: for the best performances of a factor of 6.5 and 9 for physical and chemical activation, respectively. The measured CO2 capacities are of 27.2 mg g−1 and 38.9 mg g−1 for the physically and chemically activated graphene, respectively, at 25 °C and 1 bar.

Published
2021
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2. Few-Layer Graphene-Based Nanofluids with Enhanced Thermal Conductivity

Author

Samah Hamze, Nawal Berrada, David Cabaleiro, Alexandre Desforges, Jaafar Ghanbaja, Jérôme Gleize, Dominique Bégin, Florentin Michaux, Thierry Maré, Brigitte Vigolo, and Patrice Estellé

Subjects
few-layer graphene, propylene-glycol/water, nanofluids, thermal conductivity, temperature effect, concentration influence, Chemistry, QD1-999
Abstract

High-quality graphene is an especially promising carbon nanomaterial for developing nanofluids for enhancing heat transfer in fluid circulation systems. We report a complete study on few layer graphene (FLG) based nanofluids, including FLG synthesis, FLG-based nanofluid preparation, and their thermal conductivity. The FLG sample is synthesized by an original mechanical exfoliation method. The morphological and structural characterization are investigated by both scanning and transmission electron microscopy and Raman spectroscopy. The chosen two-step method involves the use of thee nonionic surfactants (Triton X-100, Pluronic® P123, and Gum Arabic), a commercial mixture of water and propylene glycol and a mass content in FLG from 0.05 to 0.5%. The thermal conductivity measurements of the three FLG-based nanofluid series are carried out in the temperature range 283.15–323.15 K by the transient hot-wire method. From a modeling analysis of the nanofluid thermal conductivity behavior, it is finally shown that synergetic effects of FLG nanosheet size and thermal resistance at the FLG interface both have significant impact on the evidenced thermal conductivity enhancement.

Published
2020
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3. Physical and Chemical Activation of Graphene-Derived Porous Nanomaterials for Post-Combustion Carbon Dioxide Capture

Author

Brigitte Vigolo, Mélanie Emo, Rabita Mohd Firdaus, Abdul Rahman Mohamed, Alexandre Desforges, Universiti Sains Malaysia (USM), Institut Jean Lamour (IJL), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, porosity, General Chemical Engineering, Oxide, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, 01 natural sciences, Article, law.invention, Nanomaterials, symbols.namesake, chemistry.chemical_compound, Adsorption, law, medicine, General Materials Science, QD1-999, Graphene, carbon dioxide, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, Carbon black, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemistry, Chemical engineering, chemistry, adsorption, symbols, graphene oxide, activation, 0210 nano-technology, Raman spectroscopy, Activated carbon, medicine.drug
Abstract

Activation is commonly used to improve the surface and porosity of different kinds of carbon nanomaterials: activated carbon, carbon nanotubes, graphene, and carbon black. In this study, both physical and chemical activations are applied to graphene oxide by using CO2 and KOH-based approaches, respectively. The structural and the chemical properties of the prepared activated graphene are deeply characterized by means of scanning electron microscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry and nitrogen adsorption. Temperature activation is shown to be a key parameter leading to enhanced CO2 adsorption capacity of the graphene oxide-based materials. The specific surface area is increased from 219.3 m2 g−1 for starting graphene oxide to 762.5 and 1060.5 m2 g−1 after physical and chemical activation, respectively. The performance of CO2 adsorption is gradually enhanced with the activation temperature for both approaches: for the best performances of a factor of 6.5 and 9 for physical and chemical activation, respectively. The measured CO2 capacities are of 27.2 mg g−1 and 38.9 mg g−1 for the physically and chemically activated graphene, respectively, at 25 °C and 1 bar.

Published
2021
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4. From 2D graphene nanosheets to 3D graphene-based macrostructures

Author

Alexandre Desforges, Abdul Rahman Mohamed, Nawal Berrada, Brigitte Vigolo, Rabita Mohd Firdaus, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Universiti Sains Malaysia (USM)

Subjects
Chemistry, Graphene, Organic Chemistry, Nanotechnology, 02 engineering and technology, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Co2 adsorption, 01 natural sciences, Biochemistry, 6. Clean water, 0104 chemical sciences, law.invention, law, High surface area, 0210 nano-technology
Abstract

International audience; The combination of exceptional functionalities offered by 3D graphene-based macrostructures (GBMs) has attracted tremendous interest. 2D graphene nanosheets have high chemical stability, high surface area and customizable porosity, which was extensively researched for a variety of applications including CO2 adsorption, water treatment, batteries, sensors, catalysis, etc. Recently, 3D GBMs have been successfully achieved through few approaches, including direct and non-direct self-assembly methods. In this review, the possible routes used to prepare both 2D graphene and interconnected 3D-GBMs were described and analyzed regarding the involved chemistry of each 2D/3D graphene system. Improvement of the accessible surface of 3D GBMs where the interface exchanges are occurring is of great importance. A better control of the chemical mechanisms involved in the self-assembly mechanism itself at the nanometer scale is certainly the key for a future research breakthrough regarding 3D GBMs.

Published
2020
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5. Progress in adsorption capacity of nanomaterials for carbon dioxide capture: A comparative study

Author

Brigitte Vigolo, Rabita Mohd Firdaus, Abdul Rahman Mohamed, and Alexandre Desforges

Subjects
Carbon dioxide in Earth's atmosphere, Materials science, Renewable Energy, Sustainability and the Environment, Graphene, Strategy and Management, Nanotechnology, Building and Construction, Carbon nanotube, Industrial and Manufacturing Engineering, law.invention, Nanomaterials, chemistry.chemical_compound, Adsorption, chemistry, law, Carbon dioxide, Carbon capture and storage, Metal-organic framework, General Environmental Science
Abstract

With the gradual rise in atmospheric carbon dioxide brought about by human activities and industry effluents, research has now been geared toward carbon capture and storage. To achieve high carbon dioxide adsorption capacity, development of nanomaterials with optimized properties has been attracting growing interest for more than ten years already. Such multi-parameter investigations require a complex and rigorous analysis in order to compare the different developed adsorbents and improve their performances. In this review, we propose a state-of-the-art approach related to the four most studied nanostructured adsorbents for carbon dioxide capture: graphene, carbon nanotubes, zeolite, and metal organic frameworks. The capture processes and the nanomaterials of interest were described as well as the modifications applied to improve the efficiency of carbon dioxide capture. The present unprecedented analysis allows to correlate the nanomaterial properties, especially surface area and pore volume, to the CO2 adsorption capacity. The results reveal that contrary the popular belief, the CO2 capture improvement is not solely liable on the high surface area and the high pore volume of the nanosorbents. This outcome may be useful in the course of improvement of nanostructured materials for CO2 capture for future technologies.

Published
2021
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6. Volumetric Properties and Surface Tension of Few-Layer Graphene Nanofluids Based on a Commercial Heat Transfer Fluid

Author

Samah Hamze, Brigitte Vigolo, Patrice Estellé, Dominique Begin, David Cabaleiro, Alexandre Desforges, Thierry Maré, Luis Lugo, Laboratoire de Génie Civil et Génie Mécanique (LGCGM), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Universidade de Vigo, 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 Grand-Est (MNGE), 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), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), European Union through the European Regional Development Fund (ERDF) European Union (EU), Ministry of Higher Education and Research Ministry of Higher Education and Scientific Research (MHESR), French region of Brittany and Rennes Metropole, EU COST European Cooperation in Science and Technology (COST) [COST-STSM-CA15119-45590], Xunta de Galicia (Spain)Xunta de Galicia, Ministerio de Economia y Competitividad (Spain), FEDER program European Union (EU) [ENE2017-86425-C2-1-R], Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), 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), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Work (thermodynamics), Control and Optimization, Materials science, Base (chemistry), 020209 energy, water, Energy Engineering and Power Technology, Thermodynamics, 02 engineering and technology, lcsh:Technology, law.invention, Surface tension, Nanofluid, 2204 Física de Fluidos, Pulmonary surfactant, law, surface tension, Thermal, 0202 electrical engineering, electronic engineering, information engineering, 22 Física, Electrical and Electronic Engineering, Engineering (miscellaneous), propylene-glycol/water, chemistry.chemical_classification, density, nanofluids, lcsh:T, Renewable Energy, Sustainability and the Environment, Graphene, 021001 nanoscience & nanotechnology, isobaric thermal expansivity, few-layer graphene, chemistry, propylene-glycol, [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], Isobaric process, 0210 nano-technology, Energy (miscellaneous)
Abstract

Volumetric properties such as density and isobaric thermal expansivity, and surface tension are of paramount importance for nanofluids to evaluate their ability to be used as efficient heat transfer fluids. In this work, the nanofluids are prepared by dispersing few-layer graphene in a commercial heat transfer fluid Tyfocor&reg, LS (40:60 wt.% propylene-glycol/water) with the aid of three different nonionic surfactants: Triton X-100, Pluronic&reg, P-123 and Gum Arabic. The density, isobaric thermal expansivity and surface tension of each of the base fluids and nanofluids are evaluated between 283.15 and 323.15 K. The influence of the mass content in few-layer graphene from 0.05 to 0.5% on these nanofluid properties was studied. The density behavior of the different proposed nanofluids is slightly affected by the presence of graphene, and its evolution is well predicted by the weight-average equation depending on the density of each component of the nanofluids. For all the analyzed samples, the isobaric thermal expansivity increases with temperature which can be explained by a weaker degree of cohesion within the fluids. The surface tension evolution of the graphene-based nanofluids is found to be sensitive to the used surfactant, its content and the few-layer graphene concentration.

Published
2020
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7. Non-covalent and covalent immobilization of Candida antarctica Lipase B on chemically modified multiwalled carbon nanotubes for a green acylation process in supercritical CO2

Author

Jaafar Ghanbaja, Yann Guiavarc’h, Stéphane Delaunay, Mohamed Chafik Bourkaib, Fabrice Valsaque, Isabelle Chevalot, Alexandre Desforges, Nawal Berrada, Jérôme Gleize, Brigitte Vigolo, Laboratoire Réactions et Génie des Procédés (LRGP), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), Institut Jean Lamour (IJL), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Geranyl acetate, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Catalysis, supercritical CO2, [SPI.MAT]Engineering Sciences [physics]/Materials, chemistry.chemical_compound, Adsorption, Organic chemistry, Lipase, biology, carbon nanotubes, Chemistry, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, interactions, 021001 nanoscience & nanotechnology, biology.organism_classification, Lipase immobilization, green solvent, Supercritical fluid, 0104 chemical sciences, Covalent bond, biology.protein, Surface modification, Candida antarctica, 0210 nano-technology
Abstract

International audience; Candida antarctica B lipase (CAL-B) was immobilized on purified and functionalized multiwalled carbon nanotubes (MWCNTs). Both immobilization routes, physical adsorption and covalent bonding, were investigated. MWCNT functionalization by a non-aggressive oxidation by potassium permanganate led to an interesting balance between the hydrophilic and the hydrophobic areas of the MWCNT surface; the former being responsible of the good dispersion of MWCNTs in water and the latter having a favorable affinity with CAL-B. The enzyme loadings reached were significant: around 16 wt. % and 21 wt.% for non-covalent and covalent immobilization, respectively. The enzymatic activity was studied with the reaction of O-acylation of geraniol into geranyl acetate by CAL-B in supercritical CO2. Even if a decay in synthesis of geranyl acetate was observed over cycling for both CAL-B@MWCNT catalysts, it was demonstrated that the regioselectivity of CAL-B was unchanged through immobilization on the MWCNT surface for both routes. Interestingly, it was shown that a fully green enzymatic process can be achieved with these prepared CAL-B@MWCNT biocatalyst. Such approach could be transferred to other support/enzyme systems for developing new eco-friendly synthesis processes.

Published
2020
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8. Dynamic Viscosity of Purified Multi-Walled Carbon Nanotubes Water and Water-Propylene Glycol-Based Nanofluids

Author

Jaafar Ghanbaja, Thierry Maré, Samah Hamze, David Cabaleiro, Patrice Estellé, Alexandre Desforges, Jérôme Gleize, Brigitte Vigolo, Nawal Berrada, Laboratoire de Génie Civil et Génie Mécanique (LGCGM), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Universidade de Vigo, EU COST Action European Union (EU) European Cooperation in Science and Technology (COST) [CA15119], Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), and Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Thermogravimetric analysis, Nanotube, Materials science, effect of temperature and concentration, 020209 energy, 02 engineering and technology, Carbon nanotube, water-based nanofluids, Polyvinyl alcohol, law.invention, Viscosity, chemistry.chemical_compound, symbols.namesake, [SPI]Engineering Sciences [physics], Nanofluid, 0203 mechanical engineering, law, 0202 electrical engineering, electronic engineering, information engineering, Newtonian fluid, MWCNTs, Fluid Flow and Transfer Processes, Mechanical Engineering, Condensed Matter Physics, 020303 mechanical engineering & transports, Chemical engineering, chemistry, symbols, dynamic viscosity, Raman spectroscopy
Abstract

International audience; We report in this study the experimental investigation of the dynamic viscosity of purified multi-walled carbon nanotubes (MWCNT) water and water-propylene glycol-based nanofluids in the temperature range 10-80 degrees C. Four weight concentrations of MWCNTs are considered, between 0.005 and 0.1 wt.%. Triton X-100, a common nonionic surfactant, is used to disperse the nanotubes and stabilize the nanofluids as evidenced by optical characterization. Purified and non-damaged MWCNTs are used for nanofluid preparation by the two-step method. MWCNT characterization is deeply investigated from a set of complementary techniques such as thermogravimetric analysis, transmission electron microscopy, and Raman spectroscopy. The studied nanofluids behave as Newtonian fluids for low nanotube content while a shear-thinning behavior is noticed for higher concentration. Finally, the viscosity enhancement of nanofluids with MWCNT loading is compared to the modified Maron-Pierce model considering the presence of aggregates and their size obtained from optical observations.

Published
2020
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9. Surface tension of functionalized MWCNT-based nanofluids in water and commercial propylene-glycol mixture

Author

Samah Hamze, Nawal Berrada, Patrice Estellé, Jérôme Gleize, Alexandre Desforges, Brigitte Vigolo, Thierry Maré, Jaafar Ghanbaja, Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie Civil et Génie Mécanique (LGCGM), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), Université de Lorraine, European Regional Development Fund, Ministère de l'Education Nationale, de l'Enseignement Superieur et de la Recherche, Région Bretagne, Rennes Métropole, Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
Work (thermodynamics), Materials science, Base (chemistry), Nanoparticle, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, 01 natural sciences, Polyvinyl alcohol, law.invention, Surface tension, Nanofluids, chemistry.chemical_compound, Nanofluid, Effect of concentration and base fluid, law, Materials Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Spectroscopy, chemistry.chemical_classification, MWCNT, [PHYS.MECA]Physics [physics]/Mechanics [physics], 021001 nanoscience & nanotechnology, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Chemical engineering, chemistry, Hydrophobic surfaces, 0210 nano-technology, Chemical modification
Abstract

International audience; Nanofluids which consist of the addition of nanoparticles in a base fluid are envisaged for a large domain of applications. For many of them, the surface tension (ST) behavior of the prepared nanofluids is a key parameter to exploit their thermophysical properties. Due to their remarkable properties, carbon nanotubes (CNTs) are commonly used to develop nanofluids. However, the evolution of the ST of CNT-based nanofluids is still far from being understood and predictable. In the present work, two base fluids were used: water and a commercial mixture of propylene-glycol/water (around 40:60 wt%). The impact of the used multi-walled CNT (MWCNT) addition, MWCNT concentration (0.001 and 0.1 wt%) and temperature variation (273.15–333.15 K) on the density and ST evolution for the two kinds of CNT-based nanofluids is studied. The chemically modified MWCNTs are assumed to bear both localized hydrophilic areas due to grafted functional groups and remaining hydrophobic surfaces. The found difference in ST behavior between the two types of nanofluids is explained in light with the involved interfaces in each nanofluid. ST evolution is found to strongly depend on the CNT surface properties.

Published
2019
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10. Less-Nafion electrodes based on PSSA-Pt/Vulcan catalyst for PEM fuel cells

Author

Alexandre Desforges, François Lapicque, Yuzhen Xia, Caroline Bonnet, Sébastien Fontana, Gaël Maranzana, Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire Énergies et Mécanique Théorique et Appliquée (LEMTA )

Subjects
General Chemical Engineering, Proton exchange membrane fuel cell, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Analytical Chemistry, Catalysis, Electrochemical tests, Polystyrene sulfonate, [SPI]Engineering Sciences [physics], chemistry.chemical_compound, Nafion, Polymer chemistry, Electrochemistry, Ionic conductivity, Nafion amount, Sulfonate grafting Pt catalyst, 021001 nanoscience & nanotechnology, 0104 chemical sciences, PEM fuel cell, Sulfonate, chemistry, Chemical engineering, Electrode, Surface modification, 0210 nano-technology
Abstract

International audience; Functionalization on the carbon material of PEM fuel cells providing them an ionic conductivity, has been thought as a promising way to improve the catalyst activity. Pt/Vulcan catalysts grafted with polystyrene sulfonate (PSSA) groups from 5 to 20 wt.% have been prepared. Owing to the ion-exchange properties of the PSSA grafted on carbon support, we developed less-Nafion electrodes, with only 0.25 or 0.50 mg cm− 2 Nafion loading. The effect of PSSA graft ratio and the Nafion amount was studied in a single cell at 30 °C by polarization curves and impedance measurements. It was found that 5 and 10 wt.% PSSA with 0.50 mg cm− 2 Nafion allow high efficiency, however lower than 10 wt.% grafted Pt/C with 0.25 mg cm− 2 Nafion only. The performance of the various electrodes could be correlated to the overall amount of sulfonate introduced: highest yields were obtained with an overall sulfonate concentration near 0.7–0.8 μmol cm− 2.

Published
2016
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12. Protecting Carbon Nanotubes from Oxidation for Selective Carbon Impurity Elimination

Author

Brigitte Vigolo, Jaafar Ghanbaja, Emmanuel Flahaut, C. Bellouard, Jérôme Gleize, Nawal Berrada, Alexandre Desforges, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), IMPACT N4S, ANR-15-IDEX-0004,LUE,Isite LUE(2015), Centre National de la Recherche Scientifique - CNRS (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Lorraine (FRANCE), and Institut National Polytechnique de Toulouse - INPT (FRANCE)

Subjects
Materials science, Matériaux, Carbon nanotubes, chemistry.chemical_element, 02 engineering and technology, Carbon nanotube, Thermal treatment, 010402 general chemistry, 01 natural sciences, Oxygen, law.invention, [SPI.MAT]Engineering Sciences [physics]/Materials, Impurity, law, Oxidation, Chlorine, Physical and Theoretical Chemistry, 021001 nanoscience & nanotechnology, Grafting, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, Chemical engineering, chemistry, 0210 nano-technology, Selectivity, Carbon
Abstract

International audience; Purity of carbon nanotubes (CNTs) is essential to avoid a dramatic decrease in their performances. In addition to metallic impurities, carbonaceous impurities have been shown to be responsible for pronounced effects. However, they are highly difficult to be selectively removed from CNT samples because of the similar chemical reactivity of these two kinds of carbon species. The existing purification methods often lead to high CNT consumption (>90 wt %). The proposed method consists of a one-pot gas-phase treatment combining chlorine and oxygen. The CNT powder maintained in a chlorine stream is submitted to oxygen at moderate temperature [350 and 500 °C for single-walled CNTs (SWCNTs) and double-walled CNTs (DWCNTs), respectively], and the thermal treatment is then pursued at 900–1000 °C under chlorine alone. Our work reveals that this approach is able to significantly improve the selectivity of elimination of carbonaceous impurities. Thanks to the proposed purification treatment, only 19 and 11 wt % of carbon species (mainly carbon impurities) are lost for DWCNTs and SWCNTs, respectively. The mechanism proposed involves a protective effect by grafting of chlorine favored to the CNT walls. Because our simple one-pot purification method is also versatile and scalable, it opens new perspectives for CNT applications in high-added value fields.

Published
2019
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13. Dynamic Viscosity and Surface Tension of Stable Graphene Oxide and Reduced Graphene Oxide Aqueous Nanofluids

Author

Hugo Navas, Brigitte Vigolo, Patrice Estellé, David Cabaleiro, Alexandre Desforges, Laboratoire de Génie Civil et Génie Mécanique (LGCGM), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
Fluid Flow and Transfer Processes, Aqueous solution, Materials science, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Mechanics of the fluids [physics.class-ph], Graphene, Mechanical Engineering, Oxide, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, law.invention, Surface tension, chemistry.chemical_compound, Nanofluid, chemistry, Chemical engineering, law, [CHIM]Chemical Sciences, [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018
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14. Long-term Stability of Graphene Based Nanofluids

Author

Brigitte Vigolo, Hugo Navas, Patrice Estellé, Jaafar Ghanbaja, Alexandre Desforges, Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie Civil et Génie Mécanique (LGCGM), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), and Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Oxide, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, chemistry.chemical_compound, Nanofluid, Artificial Intelligence, Impurity, law, Thermal, heat transfer, Chemical reduction, [CHIM]Chemical Sciences, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, nanofluids, chemical reduction, long - term stability, Graphene, Mechanical Engineering, graphene, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chemical engineering, chemistry, Control and Systems Engineering, Heat transfer, [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], 0210 nano-technology
Abstract

International audience; Long-term stability of nanofluids remains quite challenging for graphene-based nanofluid preparation. This is however a crucial aspect for their use in heat transfer applications. In this study, we have used the derived Hummers’ method for graphene oxide preparation. Then, reduction of graphene oxide is realized in various conditions. Stability of nanofluids of graphene oxide and reduced graphene oxide are investigated. We show graphene oxide nanofluids suffer of rapid destabilization which dramatically reduces the thermal properties. Nanofluids prepared with reduced graphene oxide show an improved stability depending of the reduction conditions. NaBH4 is recommended compared to N2H4 for which impurities are introduced in the graphene structure and destabilization easily occurs.

Published
2017
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15. High-rate synthesis of graphene by a lower cost chemical vapor deposition route

Author

Abdul Rahman Mohamed, Sebastian Dayou, Alexandre Desforges, Jaafar Ghanbaja, Brigitte Vigolo, Universiti Sains Malaysia (USM), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Thermogravimetric analysis, Materials science, Nanoparticle, chemistry.chemical_element, Bioengineering, Nanotechnology, 02 engineering and technology, Chemical vapor deposition, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Catalysis, law.invention, law, [CHIM]Chemical Sciences, General Materials Science, ComputingMilieux_MISCELLANEOUS, Graphene oxide paper, Graphene, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Copper, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, chemistry, Modeling and Simulation, 0210 nano-technology, Ambient pressure
Abstract

Chemical vapor deposition (CVD) reaction from metal particles to produce graphene has seldom been reported so far. In this paper, the CVD growth of graphene was conducted under ambient pressure without a dedicated stage for reduction treatment. Interestingly, copper nanoparticles supported on MgO prepared by simple impregnation were able to efficiently catalyze graphene. Quantification of the prepared graphene was carefully conducted. For the optimized conditions, 1000 °C for 30 min, high content of graphene (up to 27 at.%) could be produced. Our method shows high efficiency and growth rate of graphene, produced at much lower cost compared to the existing methods.

Published
2017
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16. Ultrasonic treatment of glassy carbon for nanoparticle preparation

Author

Sadia Afreen, Jean-Marc Lévêque, Laurence Reinert, Manickam Sivakumar, Takahide Kimura, Laurent Duclaux, Alexandre Desforges, Naoki Komatsu, Jean-Noël Rouzaud, Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Laboratoire de géologie de l'ENS (LGENS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Shiga University of Medical Science, Centre de recherches Paul Pascal (CRPP), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nanostructure, Acoustics and Ultrasonics, Scanning electron microscope, Chemistry, Sonication, Organic Chemistry, Nanoparticle, 02 engineering and technology, Glassy carbon, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Decantation, Chemical engineering, Transmission electron microscopy, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Chemical Engineering (miscellaneous), Environmental Chemistry, Particle, Organic chemistry, Radiology, Nuclear Medicine and imaging, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

Glassy carbon particles (millimetric or micrometric sizes) dispersions in water were treated by ultrasound at 20kHz, either in a cylindrical reactor, or in a "Rosette" type reactor, for various time lengths ranging from 3h to 10h. Further separations sedimentation allowed obtaining few nanoparticles of glassy carbon in the supernatant (diameter

Published
2017
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17. Development of half-cells with sulfonated Pt/Vulcan catalyst for PEM fuel cells

Author

Caroline Bonnet, Yuzhen Xia, Thi-Thao Nguyen, Jean-François Marêché, François Lapicque, Alexandre Desforges, Sébastien Fontana, Laboratoire Réactions et Génie des Procédés ( LRGP ), Université de Lorraine ( UL ) -Centre National de la Recherche Scientifique ( CNRS ), Institut Jean Lamour ( IJL ), Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), and Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
General Chemical Engineering, Analytical chemistry, Proton exchange membrane fuel cell, Electrolyte, Electrochemistry, 7. Clean energy, Analytical Chemistry, Dielectric spectroscopy, Polystyrene sulfonate, chemistry.chemical_compound, [CHIM.GENI]Chemical Sciences/Chemical engineering, chemistry, Chemical engineering, Nafion, Cyclic voltammetry, [ CHIM.GENI ] Chemical Sciences/Chemical engineering, Voltammetry, ComputingMilieux_MISCELLANEOUS
Abstract

Half-cell is an ex situ device generally used in fuel cell investigations. The present work is related to half-cell investigations of a particular catalyst for polymer electrolyte membrane (PEM) fuel cells, namely Pt/Vulcan catalyst grafted with 5 wt.% polystyrene sulfonate (PSSA). It was found that the behavior of the half-cell to be immersed in a sulfuric solution was influenced by the hot-pressing conditions in the preparation process: optimum hot-pressing conditions had to be searched for improved, reliable performance of half cells. A stable Nafion® membrane interface on the catalytic layer (CL) was obtained at 135 °C, 40 bars for 6 min. Otherwise, owing to the ion-exchange properties of the PSSA graft, electrodes were prepared with lower amounts of Nafion® and the effect of Nafion® introduction in the preparation was discussed: test electrodes mounted in half-cell had either 0.25 or 0.50 mg cm−2 Nafion® dispersed in CL, or with 0.50 mg cm−2 deposited on CL surface. Their performances for oxygen reduction reaction (ORR) were studied using linear voltammetry (LV) and electrochemical impedance spectroscopy (EIS). Cyclic voltammetry was used for determination of the electrochemical surface area (ECSA) of each electrode. It has been shown that fresh electrodes with 0.50 mg cm−2 Nafion® dispersed in CL exhibit promoted behavior in ORR. However, the GDE prepared with Nafion® deposition on CL surface exhibits the best resistance to ageing tests performed by potential cycling between 0 and 1.2 V/NHE, as revealed by ECSA measurements.

Published
2014
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18. Dramatic enhancement of double-walled carbon nanotube quality through a one-pot tunable purification method

Author

C. Bellouard, Alexandre Desforges, Jérôme Gleize, Angélica Vieira Bridi, Joris Kadok, Brigitte Vigolo, François Le Normand, Emmanuel Flahaut, Jaafar Ghanbaja, Centre National de la Recherche Scientifique - CNRS (FRANCE), Ecole Nationale du Génie de l'Eau et de l'Environnement de Strasbourg - ENGEES (FRANCE), Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE), Institut National des Sciences Appliquées de Strasbourg - INSA (FRANCE), Université de Strasbourg - UNISTRA (FRANCE), Université Toulouse III - Paul Sabatier - UT3 (FRANCE), Université de Lorraine (FRANCE), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Centre interuniversitaire de recherche et d'ingenierie des matériaux (CIRIMAT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Les Hôpitaux Universitaires de Strasbourg (HUS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), 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), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), IMPACT N4S, ANR-15-IDEX-0004,LUE,Isite LUE(2015), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-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 National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-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)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-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)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), 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, Vigolo, Brigitte, and ISITE - Isite LUE - - LUE2015 - ANR-15-IDEX-0004 - IDEX - VALID

Subjects
Materials science, chemistry.chemical_element, 02 engineering and technology, Carbon nanotube, 010402 general chemistry, 01 natural sciences, Oxygen, Catalysis, law.invention, [CHIM.GENI]Chemical Sciences/Chemical engineering, Chlorine gas, law, Impurity, Chlorine, [CHIM]Chemical Sciences, Organic chemistry, Génie chimique, General Materials Science, Purification, [CHIM.MATE] Chemical Sciences/Material chemistry, [CHIM.GENI] Chemical Sciences/Chemical engineering, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Thermogravimetry, chemistry, Chemical engineering, Yield (chemistry), Surface modification, 0210 nano-technology
Abstract

International audience; The purification process we propose is a one-pot gas-phase treatment; the CNT powder is simply submitted to a chlorine/oxygen atmosphere at around 1000 °C for 2 h. By varying the oxygen content in an excess of chlorine, the conditions were optimized in order to efficiently remove both metal (catalyst) and carbon impurities from DWCNT samples. Even if a high amount of sample is lost under the oxidative conditions used, a selective elimination of the carbon impurities obviously occurs and a metal impurity removal yield of 99% is obtained from thermogravimetry. Based on a multi-technique approach, we show that the purified DWCNTs are of high structural quality without any surface functionalization. This improvement of the wall quality through the chlorine/oxygen action is seen in particular with a division by 15 of the D over G band intensity of the Raman spectra. Among the existing procedures, the advantages of our purification method are indisputably its simplicity, low time-consuming and high efficiency combined with an enhanced quality of the purified CNTs. Such quasi-pure DWCNTs have high interest since they offer a unique opportunity to study the intrinsic properties and effects of the nanotubes themselves.

Published
2016
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19. Solid-state chemistry route for supported tungsten and tungsten carbide nanoparticles

Author

N. Hugot, A. Albiniak, G. Furdin, Claire Hérold, Sébastien Fontana, Alexandre Desforges, and Jean-François Marêché

Subjects
Solid-state chemistry, Materials science, Mineralogy, Nanoparticle, chemistry.chemical_element, Chemical vapor deposition, Tungsten, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Inorganic Chemistry, chemistry.chemical_compound, Chemical engineering, chemistry, Tungsten carbide, Phase (matter), Materials Chemistry, Ceramics and Composites, Tungsten hexachloride, Physical and Theoretical Chemistry, Carbon
Abstract

Nanoparticles of tungsten and tungsten carbide have been prepared using solid-state chemistry methods. After the vapor phase impregnation of a tungsten hexachloride precursor on a carbon support, a temperature-programmed reduction/carburization was performed. Several parameters were investigated and the evolution of obtained samples was followed by XRD and TEM. The optimization of the reaction parameters led to the preparation of W, W2C and WC particles well dispersed on the support. WC phase however could not be obtained alone with less than 10 nm mean size. This could be explained by the carburization mechanism and the carbon diffusion on the support.

Published
2012
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20. Integrative chemistry toward the first spontaneous generation of gold nanoparticles within macrocellular polyHIPE supports (Au@polyHIPE) and their application to eosin reduction

Author

Marc Birot, Hervé Deleuze, Cédric Féral-Martin, Alexandre Desforges, Rénal Backov, Centre de recherches Paul Pascal (CRPP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires (ISM), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Université Sciences et Technologies - Bordeaux 1-Université Montesquieu - Bordeaux 4-Institut de Chimie du CNRS (INC), Department of Chemistry, Hull University, and University of Hull [United Kingdom]

Subjects
Polymers and Plastics, General Chemical Engineering, First-order reaction, 02 engineering and technology, 010402 general chemistry, Heterogeneous catalysis, 01 natural sciences, Biochemistry, Catalysis, Reduction (complexity), chemistry.chemical_compound, Polymer chemistry, Materials Chemistry, Gold nanoparticles, Environmental Chemistry, Polymer, Porosity, Eosin Y, Eosin, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, 021001 nanoscience & nanotechnology, Macrocellular foams, 0104 chemical sciences, chemistry, Chemical engineering, Colloidal gold, 0210 nano-technology
Abstract

International audience; Gold nanoparticles have been generated for the first time within open-cell macrocellular polyHIPE matrices, leading to new hybrid organic–inorganic catalytic supports labelled “Au@polyHIPE”. The overall synthesis can be realized with ease, as it is based on the spontaneous nucleation of gold nanoparticles. These new hybrid organic–inorganic materials have then been tested for heterogeneous catalysis, particularly for eosin Y reduction in the presence of NaBH4. In this reductive media the as-synthesized hybrid catalytic supports “Au@polyHIPE” exhibit a good activity. All the kinetic parameters are discussed in term of internal surface (porosity), external surface (shape), temperature and gold loading revealing a first order reaction.

Published
2007
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21. Quantitative investigation of mineral impurities of HiPco SWCNT samples: Chemical mechanisms for purification and annealing treatments

Author

Alexandre Desforges, Sébastien Fontana, Bernard Malaman, Claire Hérold, Sébastien Cahen, Ghouti Medjahdi, Jérôme Gleize, Jaafar Ghanbaja, Emeline Remy, C. Bellouard, Brigitte Vigolo, Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), and Université de Lorraine (UL)

Subjects
Materials science, Annealing (metallurgy), chemistry.chemical_element, Nanotechnology, General Chemistry, Carbon nanotube, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, law.invention, Metal, Temperature treatment, Chemical engineering, chemistry, Impurity, law, visual_art, visual_art.visual_art_medium, Chlorine, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science
Abstract

Équipe 103 : Composés intermétalliques et matériaux hybrides; International audience; HiPco single-walled carbon nanotube samples contain a non-negligible amount (about 30 wt.%) of metal-based impurities. These impurities are prejudicial to the development of CNT-based applications. In the literature, there is no agreement for their nature and their relative content. Consequently, the standard purification treatments could not be selective enough and they lead to damage the carbon nanotubes. In this work, we have deeply investigated the mineral impurities of a raw HiPco SWCNT sample by means of several techniques. We were able to identify and quantify at least six iron-based phases that coexist in the HiPco SWCNT samples. The raw SWCNTs were submitted to a selective purification treatment involving a high temperature treatment under chlorine. The results show that the efficiency of the metal removal is improved by increasing the temperature of treatment leading to a purification yield of 95.4%, while preserving the structural quality of the SWCNTs. The analysis of the mineral residues in the purified and annealed SWCNT samples allows to propose the chemical mechanisms involved during the chemical treatments.

Published
2015
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22. Synergistic Stabilization of Emulsions by a Mixture of Surface-Active Nanoparticles and Surfactant

Author

Daniel Gordon Duff, Alexandre Desforges, and Bernard P. Binks

Subjects
education.field_of_study, Chromatography, Chemistry, Population, Nanoparticle, Surfaces and Interfaces, Condensed Matter Physics, Surface tension, Contact angle, Creaming, Adsorption, Chemical engineering, Pulmonary surfactant, Emulsion, Electrochemistry, General Materials Science, education, Spectroscopy
Abstract

The stability and rheology of tricaprylin oil-in-water emulsions containing a mixture of surface-active hydrophilic silica nanoparticles and pure nonionic surfactant molecules are reported and compared with those of emulsions stabilized by each emulsifier alone. The importance of the preparation protocol is highlighted. Addition of particles to a surfactant-stabilized emulsion results in the appearance of a small population of large drops due to coalescence, possibly by bridging of adsorbed particles. Addition of surfactant to a particle-stabilized emulsion surprisingly led to increased coalescence too, although the resistance to creaming increased mainly due to an increase in viscosity. Simultaneous emulsification of particles and surfactant led to synergistic stabilization at intermediate concentrations of surfactant; emulsions completely stable to both creaming and coalescence exist at low overall emulsifier concentration. Using the adsorption isotherm of surfactant on particles and the viscosity and optical density of aqueous particle dispersions, we show that the most stable emulsions are formed from dispersions of flocculated, partially hydrophobic particles. From equilibrium contact angle and oil-water interfacial tension measurements, the calculated free energy of adsorption E of a silica particle to the oil-water interface passes through a maximum with respect to surfactant concentration, in line with the emulsion stability optimum. This results from a competition between the influence of particle hydrophobicity and interfacial tension on the magnitude of E.

Published
2006
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23. Palladium Nanoparticle Generation within Microcellular Polymeric Foam and Size Dependence under Synthetic Conditions

Author

Rénal Backov, Alexandre Desforges, Hervé Deleuze, and † and Olivier Mondain-Monval

Subjects
chemistry.chemical_classification, Materials science, General Chemical Engineering, Nucleation, Nanoparticle, chemistry.chemical_element, Nanotechnology, General Chemistry, Polymer, Industrial and Manufacturing Engineering, Catalysis, Polymerization, chemistry, Chemical engineering, Surface modification, Dispersion (chemistry), Palladium
Abstract

Microcellular polymer, known as polyHIPE, which is synthesized by polymerization of high internal phase emulsion, has been associated with heterogeneous nucleation. In this issue, we have generated palladium nanoparticles in situ by an impregnation−reduction method. The nanoparticle synthesis is very sensitive to conditions such as temperature, pH, metallic precursor, solvent, and surface chemistry of the support. We have tried to control the particle sizes and dispersion state by a careful choice of the reaction parameters and/or a suitable matrix functionalization. In a catalysis application aspect, we checked the efficiency of our supports via a hydrogenation reaction. Some of our supports offer good activity, even compared to commercial Pd/C, and also a satisfying reusability.

Published
2005
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24. Improvement of carbon nanotube stability by high temperature oxygen/chlorine gas treatment

Author

Claire Hérold, François Le Normand, Brigitte Vigolo, Jérôme Gleize, Guillaume Mercier, Alexandre Desforges, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Laboratoire de Chimie et Physique - Approche Multi-échelle des Milieux Complexes (LCP-A2MC), Université de Lorraine (UL), Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-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)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-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)-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 Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Les Hôpitaux Universitaires de Strasbourg (HUS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), 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, and 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)

Subjects
Materials science, chemistry.chemical_element, General Chemistry, Carbon nanotube, [CHIM.MATE]Chemical Sciences/Material chemistry, Combustion, Oxygen, Catalysis, law.invention, Metal, Condensed Matter::Materials Science, Chemical engineering, chemistry, Impurity, law, visual_art, visual_art.visual_art_medium, Chlorine, Organic chemistry, Surface modification, General Materials Science, Physics::Chemical Physics
Abstract

International audience; Carbon nanotubes are interesting for applications in numerous fields. Nevertheless the as-produced samples prepared from bulk synthesis methods contain impurities and remain entangled if neither mechanical nor chemical treatment is applied. Such treatments are known to damage the carbon nanotube structure and to reduce their stability which induces drastic diminution of their properties. We have developed a purification method based on the use of a gas-phase treatment under an oxygen/chlorine mixture at high temperature (around 1000 degrees C). We were able to efficiently remove metal-based impurities from catalyst residue without damaging carbon nanotubes. We show that their stability is improved thanks to the presence of chlorine-containing functional groups at the carbon nanotube surface. Under the used conditions, the functionalization level remains low preserving the SWCNT structure and efficiently protects SWCNTs from combustion by oxygen.

Published
2014
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