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1. Top‐down Surfactant‐Free Synthesis of Supported Palladium‐Nanostructured Catalysts

Author

Christian M. Schott, Peter M. Schneider, Kais Sadraoui, Kun‐Ting Song, Batyr Garlyyev, Sebastian A. Watzele, Jan Michalička, Jan M. Macak, Arnaud Viola, Frédéric Maillard, Anatoliy Senyshyn, Johannes A. Fischer, Aliaksandr S. Bandarenka, and Elena L. Gubanova

Subjects
electrochemical erosion, hydrogen embrittlement, hydrogen evolution reaction, nanoparticles, palladium, Materials of engineering and construction. Mechanics of materials, TA401-492
Abstract

Nanostructured palladium (Pd) is a universal catalyst that is widely used in applications ranging from catalytic converters of combustion engine cars to hydrogenation catalysts in industrial processes. Standard protocols for synthesizing such nanoparticles (NPs) typically use bottom‐up approaches. They utilize special and often expensive physical techniques or wet‐chemical methods requiring organic surfactants. These surfactants should often be removed before catalytic applications. In this article, the synthesis of Pd NPs immobilized on carbon support by electrochemical erosion without using any surfactants or toxic materials is reported. The Pd NPs synthesis essentially relies on a Pd bulk pretreatment, which causes material embrittlement and allows the erosion process to evolve more efficiently, producing homogeneously distributed NPs on the support. Moreover, the synthesized catalyst is tested for hydrogen evolution reaction. The activity evaluations identify optimal synthesis parameters related to the erosion procedure. The electrocatalytic properties of the Pd NPs produced with sizes down to 6.4 ± 2.9 nm are compared with a commercially available Pd/C catalyst. The synthesized catalyst outperforms the commercial catalyst within all properties, like specific surface area, geometric activity, mass activity, specific activity, and durability.

Published
2024
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2. Break-In Bad: On the Conditioning of Fuel Cell Nanoalloy Catalysts

Author

Raphaël Chattot, Camille Roiron, Kavita Kumar, Vincent Martin, Carlos Augusto Campos Roldan, Marta Mirolo, Isaac Martens, Luis Castanheira, Arnaud Viola, Rémi Bacabe, Sara Cavaliere, Pierre-Yves Blanchard, Laetitia Dubau, Frédéric Maillard, and Jakub Drnec

Subjects
General Chemistry, Catalysis
Published
2022
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3. Imaging the strain evolution of a platinum nanoparticle under electrochemical control

Author

Clément Atlan, Corentin Chatelier, Isaac Martens, Maxime Dupraz, Arnaud Viola, Ni Li, Lu Gao, Steven J. Leake, Tobias U. Schülli, Joël Eymery, Frédéric Maillard, Marie-Ingrid Richard, European Synchroton Radiation Facility [Grenoble] (ESRF), Electrochimie Interfaciale et Procédés (EIP), Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces (LEPMI), Institut de Chimie du CNRS (INC)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Institut de Chimie du CNRS (INC)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Nanostructures et Rayons X (NRX), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Eindhoven University of Technology [Eindhoven] (TU/e), and European Project: 818823,CARINE

Subjects
[PHYS.MECA.MEMA]Physics [physics]/Mechanics [physics]/Mechanics of materials [physics.class-ph], Mechanics of Materials, Mechanical Engineering, General Materials Science, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, Condensed Matter Physics
Abstract

International audience; Surface strain is widely employed in gas phase catalysis and electrocatalysis to control the binding energies of adsorbates on active sites. However, in situ or operando strain measurements are experimentally challenging, especially on nanomaterials. Here, we exploit coherent diffraction at the new 4 th generation Extremely Brilliant Source at the European Synchrotron Radiation Facility (ESRF-EBS) to map and quantify strain inside individual Pt catalyst nanoparticles under electrochemical control. 3D nanoresolution strain microscopy together with density functional theory and atomistic simulations show for the first time evidence of heterogeneous and potential-dependent strain distribution between highly-coordinated ({100} and {111} facets) and under-coordinated atoms (edges and corners) as well as evidence of strain propagation from the surface to the bulk of the nanoparticle. These dynamic structural relationships directly inform the design of strain-engineered nanocatalysts for energy storage and conversion applications.

Published
2023
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4. On the importance of the crystalline surface structure on the catalytic activity and stability of tailored unsupported cobalt nanoparticles for the solvent-free acceptor-less alcohol dehydrogenation

Author

Alexandre Chevillot-Biraud, Patricia Beaunier, L. Sicard, Arnaud Viola, Jean-Yves Piquemal, Philippe Lang, Sophie Nowak, Marion Giraud, Philippe Decorse, and Jennifer Peron

Subjects
Materials science, Absorption spectroscopy, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Catalysis, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry, Chemical engineering, Dehydrogenation, Nanorod, Carboxylate, 0210 nano-technology, Selectivity, Cobalt
Abstract

Unsupported nanoparticles are now recognized as model catalysts to evaluate the intrinsic activity of metal particles, irrespectively of that of the support. Co nanoparticles with different morphologies, rods, diabolos and cubes have been prepared by the polyol process and tested for the acceptorless catalytic dehydrogenation of alcohols under solvent-free conditions. Rods crystallize with the pure hcp structure, diabolos with a mixture of hcp and fcc phases, while the cubes crystallize in a complex mixture of hcp, fcc and e-Co phases. All the cobalt particles are found to be highly selective towards the oxidation of a model secondary alcohol, octan-2-ol, into the corresponding ketone while no significant activity is found with octan-1-ol. Our results show the strong influence of particle shape on the activity and catalytic stability of the catalysts: Co nanorods display the highest conversion (85%), selectivity (95%) and recyclability compared to Co diabolos and Co cubes. We correlate the nanorods excellent stability with a strong binding of carboxylate ligands on their {1 1 2 ¯ 0} facets, preserving their crystalline superficial structure, as evidenced by phase modulation infrared reflection absorption spectroscopy.

Published
2020
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5. (Invited) Benchmarking Oxygen Evolution Reaction Activity and Stability of Unsupported and Supported IrOx Nanoparticles

Author

Camila Daiane Ferreira da Silva, Fabien Claudel, Sofyane Abbou, Arnaud Viola, Raphaël Chattot, Vincent Martin, Jennifer Peron, Marco Faustini, Laetitia Dubau, and Frederic Maillard

Abstract

Proton-exchange membrane water electrolyzers (PEMWEs) electrodes use scarce and costly platinum group metals (PGMs), but only such devices are able to meet the requirements associated with renewable energies (large amplitude and frequent and rapid variations in the current applied to the cell). Catalysts represent only 8 % to the overall stack cost, 6 % being associated with the high iridium (Ir) loading used to electrocatalyze the anodic oxygen evolution reaction (OER). High surface area supported Ir oxide (IrOx) catalysts thus represent a promising strategy to reduce the cost of this technology and limit the geological pressure on Ir. However, the Gibbs-Thompson effect, which controls the electrochemical stability of nanomaterials casts a doubt on the viability of this approach. To shed light into the benefits and limitations of supported and unsupported IrOx catalysts, we benchmarked commercial materials (unsupported IrO2, Ir/C), unsupported porous IrOx microparticles, and IrOx nanoparticles (NPs) supported on carbon black or on doped tin oxide aerogels (AG)/nanofibers (NFs). Transmission electron microscopy (TEM) and identical-location transmission electron microscopy (IL-TEM) provided changes in morphology during accelerated stress testing. Complementarily, a flow cell connected to an inductively-coupled mass spectrometer (FC-ICP-MS) was used to assess their stability number (S-number, see Figure 1). The results show that supported IrOx nanocatalysts are extremely active toward the OER because they feature mixed Ir oxidation states and a high density of active sites (small crystallite/particle size). The lack of robustness of their supports, however, prevents the nanocatalysts from sustaining this high OER activity [1, 2]. Similar to what was observed on extended surfaces, we report that mild thermal annealing (450°C) leads to lower Ir atom dissolution rate. Overall, the best compromise between OER activity and stability was obtained for unsupported porous IrOx microparticles after mild thermal annealing under air at 450°C [2]. On the cathode side, IL-TEM measurements revealed mild changes in morphology for Pt/C nanoparticles [3]. Ackowledgements This work was supported by the French National Research Agency in the frame of the MOISE project (grant number ANR-17-CE05-0033). References S. Abbou, R. Chattot, V. Martin, F. Claudel, L. Solà-Hernández, C. Beauger, L. Dubau, F. Maillard, ACS Catal. 10 (2020) 7283-7284. C. Daiane Ferreira da Silva, F. Claudel, V. Martin, R. Chattot, S. Abbou, K. Kumar, I. Jiménez-Morales, S. Cavaliere, D. Jones, J. Rozière, L. Solà-Hernandez, C. Beauger, M. Faustini, J. Peron, B. Gilles, C. Beauger, L. Piccolo, F. H. Barros de Lima, L. Dubau, F. Maillard, ACS Catal. 11 (2021) 4107-4116. A. Viola, L. Dubau, F. Maillard, in preparation. Figure 1. S-number values calculated for supported and unsupported IrOx electrocatalysts during a galvanostatic accelerated stress test (j = 10 mA cm-2 geo, T = 80 °C, U cut-off = 2 V vs. RHE) performed in Ar-saturated 0.05 M H2SO4. Reprinted with permission from ref. [2]. Copyright 2021 American Chemical Society. Figure 1

Published
2022
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6. Importance of the decoration in shaped cobalt nanoparticles in the acceptor-less secondary alcohol dehydrogenation

Author

Jean-Yves Piquemal, Arthur Moisset, Kamila Kaźmierczak, Arnaud Viola, Guillaume Viau, Michèle Besson, L. Sicard, Jennifer Peron, Noémie Perret, Carine Michel, Marion Giraud, Raj Kumar Ramamoorthy, Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Nanomagnétisme (LPCNO), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-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)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), ANR-15-CE07-0011,TANOPOL,Des nanocatalyseurs sur mesure pour l'oxydation catalytique sélective de poly-alcools(2015), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
Chemistry, Ligand, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Combinatorial chemistry, [SDE.ES]Environmental Sciences/Environmental and Society, Catalysis, 0104 chemical sciences, Turnover number, Metal, chemistry.chemical_compound, visual_art, visual_art.visual_art_medium, Dehydrogenation, Carboxylate, 0210 nano-technology, Cobalt
Abstract

SSCI-VIDE+CDFA+MBE:NPR; International audience; Metal catalysts are essential in the production of fuels and chemicals. Nonetheless, tailoring the exposed active sites to achieve the maximal theoretical conversion is still a great challenge. In the case of structure-sensitive reactions, such as the attractive acceptor-less alcohol dehydrogenation, playing on the exposed metallic sites appears as an appealing strategy. Still, this approach requires advanced preparation protocols and is even more difficult to implement for supported non-noble metal catalysts which easily undergo sintering. Using the polyol method, we synthesized fourteen different cobalt catalysts, which consist of unsupported shaped nanoparticles stabilized by adsorbed carboxylate ligands. Their shape and the amount of ligands were characterized by combining TEM and TGA-N2 measurements. These catalysts were found to be active in the 2-octanol dehydrogenation conditionally upon an organic layer limited to 1 to 2 monolayers. Moreover, they were fully selective towards the desired ketone and H2. The active catalysts were stable, with no leaching or modification of the shape during the reaction. Periodic DFT computations predict a greater activity of the pristine open-type facet than of the compact one, but this is not confirmed experimentally with no clear correlation between the activity expressed in turnover number and the amount of a given type of site as quantified by TEM. Further modeling including the organic layer shows that the presence of ligands reduces the sensitivity to the metallic structure. Nonetheless, these ligands generate a catalytic pocket, similar to the one found in enzymes, that interacts with the alcohol substrate through H-bonding. This pocket is the most adapted to the alcohol dehydrogenation on the open-type facet, which is mainly exposed on rods. This detailed understanding paves the way to an improved design of bespoke unsupported catalysts considering simultaneously the structure and the nature of the ligand.

Published
2020
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7. One-Pot Seed-Mediated Growth of Co Nanoparticles by the Polyol Process: Unraveling the Heterogeneous Nucleation

Author

Jean-Yves Piquemal, Christophe Gatel, Guillaume Viau, Martin Hÿtch, Raj Kumar Ramamoorthy, Arnaud Viola, Bilel Grindi, Jennifer Peron, Raul Arenal, L. Sicard, Marion Giraud, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), 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)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Agence Nationale de la Recherche (France), Ministerio de Economía y Competitividad (España), European Commission, Gatel, Christophe, Arenal, Raul, Giraud, Marion, Viau, Guillaume, Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Gatel, Christophe [0000-0001-5549-7008], Arenal, Raul [0000-0002-2071-9093], Giraud, Marion [0000-0003-1810-7626], and Viau, Guillaume [0000-0001-7062-4183]

Subjects
chemistry.chemical_classification, Materials science, Geometric phase analysis, Mechanical Engineering, Nucleation, Nanoparticle, Bioengineering, Good control, 02 engineering and technology, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Polyol, chemistry, Chemical engineering, Cobalt nanoparticles, Polyol synthesis, Scientific method, Particle, General Materials Science, Seed mediated, HAADF-STEM, 0210 nano-technology, Metal nanoparticles
Abstract

The one-step seed-mediated synthesis is widely used for the preparation of ferromagnetic metal nanoparticles (NPs) since it offers a good control of particle morphology. Nevertheless, this approach suffers from a lack of mechanistic studies because of the difficulties of following in real time the heterogeneous nucleation and predicting structure effects with seeds that are generated in situ. Here, we propose a complete scheme of the heteronucleation process involved in one-pot seed-mediated syntheses of cobalt nanoparticles in liquid polyols, relying on geometrical phase analysis (GPA) of high-resolution high-angle annular dark field (HAADF)-STEM images and in situ measurements of the molecular hydrogen evolution. Cobalt particles of different shapes (rods, platelets, or hourglass-like particles) were grown by reducing cobalt carboxylate in liquid polyols in the presence of iridium or ruthenium chloride as the nucleating agent. A reaction scheme was established by monitoring the H2 evolution resulting from the decomposition of metal hydrides, formed in situ by β-elimination of metal alkoxides, and from the polyol dehydrogenation, catalytically activated by the metal particles. This is a very good probe for both the noble metal nucleation and the heterogeneous nucleation of cobalt, showing a good separation of these two steps. Ir and Ru seeds with a size in the range 1–2 nm were found exactly in the center of the cobalt particles, whatever the cobalt particle shape, and high-resolution images revealed an epitaxial growth of the hcp Co on fcc Ir or hcp Ru seeds. The microstructure analysis around the seeds made evident two different ways of relaxing the lattice mismatch between the seeds and the cobalt, with the presence of dislocations around the Ir seeds and compression zones of the cobalt lattice near the Ru seeds. The relationship between the nature of the nucleating agent, the reaction steps, and the microstructure is discussed., This work was funded by the French National Research Agency, ANR, in the framework of the TANOPOL project (ANR-15-CE07-0011-01). Angélique Gillet is warmly thanked for the nanoparticle synthesis, and Lucien Datas and Teresa Hungria (Plateforme Castaing, Toulouse) are thanked for HAADF-STEM images. We gratefully acknowledge the International Associated Laboratory (LIA)-M2ZART for financial support. High-resolution HAADF-STEM images were performed at the Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Spain. R.A. gratefully acknowledges the support from the Spanish Ministry of Economy and Competitiveness (MINECO) through Project MAT2016-79776-P (AEF/FEDER. UE) and from the European Union H2020 program “ESTEEM3” (823717).

Published
2019
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8. Biobased epoxy thermosets from vanillin-derived oligomers

Author

Sylvain Caillol, Maxence Fache, Rémi Auvergne, Bernard Boutevin, Arnaud Viola, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, Polymers and Plastics, Vanillin, Organic Chemistry, lignin, General Physics and Astronomy, Thermosetting polymer, Epoxide, Epoxy, Oligomer, epoxy, biobased polymer, chemistry.chemical_compound, [CHIM.POLY]Chemical Sciences/Polymers, Monomer, vanillin, chemistry, thermoset, Yield (chemistry), visual_art, Materials Chemistry, visual_art.visual_art_medium, Organic chemistry, Glass transition, ComputingMilieux_MISCELLANEOUS
Abstract

Novel vanillin-derived epoxy oligomers were prepared and crosslinked to yield biobased epoxy thermosets. This work directly continues the efforts engaged by our team to use vanillin as a renewable building block for polymer chemistry as it is an industrially available, non-toxic, wood-derived compound. The oligomers were synthesized by adapting and optimizing an industrial strategy currently in use, consisting in the chain-extension of a diepoxy monomer in excess by the poly(addition) of a diphenol. The length of the oligomers prepared was controlled by the stoichiometry of the reactants, and well-predicted by Carothers’ equation. A 1H NMR titration method was implemented to determine the epoxide indexes of the oligomers, which were very close to the ones calculated. The thermal properties of the oligomers were investigated and their Tg increased with the chain length, in accordance with the Flory–Fox equation. Thermosets were prepared by crosslinking these biobased epoxy oligomers with a common industrial amine hardener. The materials obtained displayed good thermo-mechanical properties that were tunable with the chain length of the oligomer employed. The current strategy used in industry was found to be applicable to renewable resources-based epoxy resins.

Published
2015
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9. Unsupported shaped cobalt nanoparticles as efficient and recyclable catalysts for the solvent-free acceptorless dehydrogenation of alcohols

Author

Noémie Perret, Marion Giraud, Jean-Yves Piquemal, Michèle Besson, Jennifer Peron, K. Kazmierczak, Mickaël Sicard, Arnaud Viola, Carine Michel, Patricia Beaunier, L. Sicard, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes - École supérieure du professorat et de l'éducation - Académie de Grenoble (UGA ESPE Grenoble), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-C'Durable (CDURABLE), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Laboratoire de Réactivité de Surface (LRS), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universitat Politècnica de Catalunya [Barcelona] (UPC), ANR-15-CE07-0011,TANOPOL,Des nanocatalyseurs sur mesure pour l'oxydation catalytique sélective de poly-alcools(2015), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), École supérieure du professorat et de l'éducation - Académie de Grenoble (ESPE Grenoble), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Grenoble Alpes (UGA), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), IRCELYON-Chimie durable: du fondamental à l'application (CDFA), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), ANR-15-CE07-0011,TANOPOL,Des nanocatalyseurs sur mesure pour l'oxydation catalytique sélective de poly-alcools(2016), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier ( ICGM ICMMM ), Université Montpellier 1 ( UM1 ) -Université Montpellier 2 - Sciences et Techniques ( UM2 ) -Ecole Nationale Supérieure de Chimie de Montpellier ( ENSCM ) -Université de Montpellier ( UM ) -Centre National de la Recherche Scientifique ( CNRS ), École supérieure du professorat et de l'éducation - Académie de Grenoble ( ESPE Grenoble ), Université Savoie Mont Blanc ( USMB [Université de Savoie] [Université de Chambéry] ) -Université Grenoble Alpes ( UGA ), Cognition, Action, et Plasticité Sensorimotrice [Dijon - U1093] ( CAPS ), Université de Bourgogne ( UB ) -Institut National de la Santé et de la Recherche Médicale ( INSERM ), Interfaces, Traitements, Organisation et Dynamique des Systèmes ( ITODYS UMR7086 ), Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Chemical Engineering, Heriot-Watt University [Edinburgh] ( HWU ), Laboratoire de Réactivité de Surface ( LRS ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Universitat Politècnica de Catalunya [Barcelona] ( UPC ), Institut de recherches sur la catalyse et l'environnement de Lyon ( IRCELYON ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC)

Subjects
chemistry.chemical_classification, 010405 organic chemistry, chemistry.chemical_element, Primary alcohol, 010402 general chemistry, Heterogeneous catalysis, 7. Clean energy, 01 natural sciences, Aldehyde, [ CHIM ] Chemical Sciences, Catalysis, 12. Responsible consumption, 0104 chemical sciences, chemistry, Alcohol oxidation, Organic chemistry, [CHIM]Chemical Sciences, Dehydrogenation, Chemoselectivity, Cobalt
Abstract

International audience; Oxidation of alcohols is a key-reaction for the valorization of biomass compounds, and green processes are preferred to avoid the use or production of toxic compounds. In this context, unsupported nanometer-sized catalysts have emerged as very promising materials for heterogeneous catalysis. In this paper we explore the catalytic activity of unsupported cobalt nanoparticles towards the dehydrogenation of aliphatic primary and secondary alcohols under solvent-free conditions. The unsupported particles are found to be highly active for the conversion of secondary alcohol to the corresponding ketone vs. the primary alcohol. The oxidation process is following an acceptorless dehydrogenation mechanism, where the only by-product of the reaction is the highly valuable H2 molecule. DFT calculations evidence that the chemoselectivity of secondary vs. primary alcohols originates from a more favorable desorption of the ketone reaction product compared to the aldehyde. It is also found that the morphology of the particles has a strong influence on the catalyst efficiency and stability: Co nanorods can be recycled at least three times without a loss in catalytic performances.

Published
2018
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10. Control of the crystal habit and magnetic properties of Co nanoparticles through the stirring rate

Author

Christian Ricolleau, Jean-Yves Piquemal, Silvana Mercone, Lise-Marie Lacroix, M. Abderraba, K. Mrad, Noureddine Jouini, Frédéric Schoenstein, Arnaud Viola, L. Mouton, Guillaume Viau, H. Nong, Evangelia Anagnostopoulou, Laboratoire des Sciences des Procédés et des Matériaux (LSPM), Université Paris 13 (UP13)-Institut Galilée-Université Sorbonne Paris Cité (USPC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Interfaces, Traitements, Organisation et Dynamique des Systèmes (ITODYS (UMR_7086)), Université Paris Diderot - Paris 7 (UPD7)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Matériaux, Molécules et Applications (LMMA), Université de Carthage - University of Carthage-Institut préparatoire aux études scientifiques et techniques [La Marsa] (IPEST), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-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)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Diffusion, chemistry.chemical_element, Nanoparticle, Nanotechnology, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, chemistry, Chemical engineering, Ferromagnetism, Surface roughness, Particle, [CHIM]Chemical Sciences, General Materials Science, Crystal habit, 0210 nano-technology, Cobalt, Stacking fault
Abstract

International audience; Ferromagnetic hcp cobalt nanoparticles (NPs) are prepared by the polyol process using long-chain carboxylates as shape-directing agents, applying different stirring rates during the synthesis. Particles prepared with a stirring rate lower than ca. 150 rpm are very well-defined anisotropic crystals with smooth lateral facets and low stacking fault densities. The growth proceeds along the c axis of the hcp structure which corresponds to the long axis of the anisotropic particles. Increasing the stirring speed leads to a lowering of the mean aspect ratio, an increase in structural disorder as well as to a strong modification of the particle habit. The resulting Co NPs then display a marked surface roughness. We propose here a mechanism to explain the different morphologies observed. A high stacking fault density triggers the local disorganisation of the adsorbed capping agent layer which in turn favours the diffusion of Co monomers through the organic layer, resulting in the formation of excrescences perpendicular to the long axis of the particles. The magnetic properties are strongly related to the morphological and micro-structural properties of the particles. The stirring rate appears, so far, as the driving force to control the magnetic properties of the NPs from hard magnetic behaviour at low stirring rates to an almost soft magnetic one under high stirring conditions.

Published
2017

11. Analyse statistique des écarts à l'étalonnage des capteurs de niveau piézométriques

Author

Arnaud Viola and Christian Roux

Subjects
Empirical error, Quality (physics), Computer science, Calibration (statistics), Statistics, Error band, Cartography, Statistic, Water Science and Technology
Abstract

This paper describes the error of measurement statistic of piezometric depth sensors in sewer network. Annual calibration results of 250 sensors operated for more than 10 years by the Seine-Saint-Denis country are analysed. Deviation between the measurement given by the sensor and the measurement given by a working standard are scattered in an empirical error band 1.5 time larger than the error band provided by the manufacturer. Results show a link between the non conformity rate and the following factors: the sensor age, the kind of sewer in which it is used, the quality of the sewer water, the sensor antecedents.

Published
2001
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