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28 results on '"Camille La Fontaine"'

1. Bismuth mobile promoter and cobalt-bismuth nanoparticles in carbon nanotube supported Fischer-Tropsch catalysts with enhanced stability

Author

Alan J. Barrios, Vitaly V. Ordomsky, Camille La Fontaine, Andrei Y. Khodakov, Bang Gu, Thobani G. Gambu, Siddardha Koneti, Mark Saeys, Deizi V. Peron, Simona Moldovan, Mykhailo Vorokhta, Břetislav Šmíd, Mirella Virginie, Valérie Briois, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Charles University [Prague] (CU), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Groupe de physique des matériaux (GPM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Chemical Technology, Universiteit Gent = Ghent University (UGENT), UCCS Équipe Catalyse Supramoléculaire, Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique

Subjects
Technology and Engineering, INITIO MOLECULAR-DYNAMICS, XAS, chemistry.chemical_element, Sintering, Nanoparticle, 02 engineering and technology, Carbon nanotube, REDUCIBILITY, 010402 general chemistry, RAY-ABSORPTION-SPECTROSCOPY, 7. Clean energy, 01 natural sciences, Catalysis, Fischer-Tropsch, law.invention, Bismuth, law, XPS, LIGHT OLEFINS, [CHIM]Chemical Sciences, Operando, Physical and Theoretical Chemistry, Bimetallic strip, ComputingMilieux_MISCELLANEOUS, Fischer–Tropsch process, Cobalt, 021001 nanoscience & nanotechnology, MULTIVARIATE CURVE RESOLUTION, 0104 chemical sciences, IRON CATALYSTS, MCR-ALS, chemistry, Chemical engineering, CO CATALYSTS, 0210 nano-technology, Stability, Liquid metals
Abstract

Metal nanoparticles on the surface of porous supports have found numerous applications in different areas of science. Fischer-Tropsch synthesis, which proceeds on the surface of cobalt metal nanoparticles, is an efficient way to convert renewables and fossil feedstocks into alternative fuels. The stability of cobalt catalysts is an essential and even crucial parameter and can be significantly improved by promotion. In this paper, a combination of operando Quick-XAS, NAP-XPS, high resolution electron microscopy imaging, DFT modeling alongside with Fischer-Tropsch catalytic experiments has provided deep insights into the evolution of bismuth promoter and structure of cobalt-bismuth nanoparticles in the catalysts supported by carbon nanotubes. We uncovered noticeable migration of metallic bismuth occurring during the reduction step, which leads to bismuth redispersion over the surface of cobalt nanoparticles. Cobalt reduction is facilitated in the presence of bismuth. The working Fischer-Tropsch catalyst contains cobalt-bismuth bimetallic nanoparticles, with bismuth located in the nanoparticle shell. The promotion with bismuth has resulted in a noticeable increase in catalyst stability. Characterization and DFT modeling suggest preferential localization of bismuth mobile promoter at the steps and edges of cobalt nanoparticles, which hinders cobalt sintering and carbon deposition and improves the catalyst stability.

Published
2021
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2. Investigation of the Reducibility of Supported Oxomolybdate Species for Mapping of Active Centers of Partial Oxidation Reaction: In Situ Mo K-Edge XAS and DFT Study

Author

Elise Berrier, Camille La Fontaine, Hao Hu, Sylvain Cristol, Jean-François Paul, Asma Tougerti, Danilo Oliveira de Souza, Valérie Briois, DTU Fotonik - Department of Photonics Engineering, Technical University of Denmark [Lyngby] (DTU), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Danmarks Tekniske Universitet = Technical University of Denmark (DTU), and Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
In situ, X-ray absorption spectroscopy, Materials science, [CHIM.CATA]Chemical Sciences/Catalysis, 02 engineering and technology, Electronic structure, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, General Energy, chemistry, K-edge, Phase (matter), Physical chemistry, Partial oxidation, Methanol, Physical and Theoretical Chemistry, Absorption (chemistry), 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

We have investigated the molecular and electronic structure of a TiO2-supported oxomolybdate phase upon reduction under methanol or dihydrogen atmosphere. In situ Mo K-edge X-ray absorption spectro...

Published
2019
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3. Insight into the thermal decomposition of ammonium hexahalogenoiridates(IV) and hexachloroiridate(III)

Author

Sergey V. Korenev, S. A. Martynova, Igor P. Asanov, Kirill V. Yusenko, Pavel E. Plyusnin, A. I. Gubanov, Valentina V. Zvereva, Olga Roudenko, Camille La Fontaine, and Tatyana I. Asanova

Subjects
Materials science, Extended X-ray absorption fine structure, Thermal decomposition, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Metal, chemistry.chemical_compound, chemistry, visual_art, visual_art.visual_art_medium, Physical chemistry, Ammonium, Iridium, Physical and Theoretical Chemistry, 0210 nano-technology, Inert gas
Abstract

Thermal decomposition of (NH4)3[IrCl6]·H2O, (NH4)2[IrCl6] and (NH4)2[IrBr6] in reductive and inert atmospheres has been investigated in situ using quick-EXAFS and temperature-resolved powder X-ray diffraction. For the first time, (NH4)2[Ir(NH3)Cl5] and (NH4)2[Ir(NH3)Br5] have been proven as intermediates of thermal decomposition of (NH4)3[IrCl6]·H2O, (NH4)2[IrCl6] and (NH4)2[IrBr6]. Thermal degradation of (NH4)2[IrCl6] and (NH4)2[IrBr6] is a more complex process as suggested previously and includes simultaneous formation of (NH4)2[Ir(NH3)Cl5] and (NH4)2[Ir(NH3)Br5] intermediates mixed with metallic iridium. In the inert atmosphere, complexes (NH4)[Ir(NH3)2Cl4] and (NH4)[Ir(NH3)2Br4] as well as [Ir(NH3)3Br3] were proposed as possible intermediates before formation of metallic iridium particles.

Published
2020

4. Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions

Author

Angelika Brückner, Camille La Fontaine, Ursula Bentrup, Jabor Rabeah, Valérie Briois, Sven Adomeit, Centre National de la Recherche Scientifique (CNRS), and Synchrotron SOLEIL (SSOLEIL)

Subjects
Reaction mechanism, coupled operando spectroscopy, Dimer, ATR-IR, Infrared spectroscopy, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Catalysis, law.invention, Bipyridine, chemistry.chemical_compound, law, Electron paramagnetic resonance, Spectroscopy, X-ray absorption spectroscopy, Full Paper, Extended X-ray absorption fine structure, 010405 organic chemistry, Chemistry, Organic Chemistry, General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, Full Papers, XANES, 0104 chemical sciences, EXAFS, Crystallography, EPR, reaction mechanism
Abstract

Operando EPR, XANES/EXAFS, UV‐Vis and ATR‐IR spectroscopic methods have been coupled for the first time in the same experimental setup for investigation of unclear mechanistic aspects of selective aerobic oxidation of benzyl alcohol by a Cu/TEMPO catalytic system (TEMPO=2,2,6,6‐tetramethylpiperidinyloxyl). By multivariate curve resolution with alternating least‐squares fitting (MCR‐ALS) of simultaneously recorded XAS and UV‐Vis data sets, it was found that an initially formed (bpy)(NMI)CuI‐ complex (bpy=2,2′‐bipyridine, NMI=N‐methylimidazole ) is converted to two different CuII species, a mononuclear (bpy)(NMI)(CH3CN)CuII‐OOH species detectable by EPR and ESI‐MS, and an EPR‐silent dinuclear (CH3CN)(bpy)(NMI)CuII(μ‐OH)2 ⋅CuII (bpy)(NMI) complex. The latter is cleaved in the further course of reaction into (bpy)(NMI)(HOO)CuII‐TEMPO monomers that are also EPR‐silent due to dipolar interaction with bound TEMPO. Both Cu monomers and the Cu dimer are catalytically active in the initial phase of the reaction, yet the dimer is definitely not a major active species nor a resting state since it is irreversibly cleaved in the course of the reaction while catalytic activity is maintained. Gradual formation of non‐reducible CuII leads to slight deactivation at extended reaction times., X‐ray meets magnet and chemometrics: Benefits of a new 4‐in‐one spectroscopy installed at a synchrotron and supported by chemometric evaluation of results are demonstrated using aerobic Cu/TEMPO catalyzed alcohol oxidation as model reaction.

Published
2020
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5. Quick-EXAFS and Raman monitoring of activation, reaction and deactivation of NiCu catalysts obtained from hydrotalcite-like precursors

Author

Camille La Fontaine, Celso Valentim Santilli, Sandra Helena Pulcinelli, Aline Ribeiro Passos, Valérie Briois, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP), Soleil Synchrotron, Brazilian Center for Research in Energy and Materials (CNPEM), and Universidade Estadual Paulista (Unesp)

Subjects
inorganic chemicals, Hydrotalcite, General Physics and Astronomy, chemistry.chemical_element, [CHIM.CATA]Chemical Sciences/Catalysis, 02 engineering and technology, Coke, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, Copper, 0104 chemical sciences, Catalysis, Amorphous solid, Steam reforming, Nickel, symbols.namesake, chemistry, Chemical engineering, symbols, Physical and Theoretical Chemistry, 0210 nano-technology, Raman spectroscopy
Abstract

Made available in DSpace on 2021-06-25T11:04:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-09-14 The understanding of phase transformation upon activation, reaction and deactivation of catalysts is of prime importance for tailoring catalysts with better performances. Herein we combined Quick-EXAFS and Raman spectroscopies in operando conditions through the monitoring of reaction products by mass spectrometry in order to study in depth active species and deactivating ones for Ethanol Steam Reforming reaction. Quick-EXAFS data analyzed by multivariate analysis allows one to determine the nickel and copper species involved during the activation of a Ni-Cu hydrotalcite-like precursors. Upon reaction and regeneration monitoring, Raman spectroscopy combined with mass spectrometry highlights the side products formed upon ESR leading to the formation of amorphous coke species encapsulating active metallic species and inducing catalyst deactivation. The coke encapsulation of active species was demonstrated by the simultaneous observation of oxidation of nickel and copper as soon as the amorphous coke was burnt by the oxidative regeneration treatment. Formation of filamentous coke species is also confirmed as causing little impact in catalyst deactivation. Soleil Synchrotron, L'Orme des Merisiers BP48 Brazilian Synchrotron Light Laboratory (LNLS) Brazilian Center for Research in Energy and Materials (CNPEM) Chemistry Institute of the São Paulo State University Unesp Chemistry Institute of the São Paulo State University Unesp

Published
2020
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6. Operando XAS/Raman/MS monitoring of ethanol steam reforming reaction–regeneration cycles

Author

Valérie Briois, Celso Valentim Santilli, Camille La Fontaine, Aline Ribeiro Passos, Sandra Helena Pulcinelli, Leandro Martins, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Universidade Estadual Paulista Júlio de Mesquita Filho = São Paulo State University (UNESP), and Instituto de Quimica (UNESP)

Subjects
inorganic chemicals, Kirkendall effect, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, complex mixtures, 7. Clean energy, 01 natural sciences, Catalysis, Steam reforming, chemistry.chemical_compound, symbols.namesake, ComputingMilieux_MISCELLANEOUS, X-ray absorption spectroscopy, Ethanol, [CHIM.CATA]Chemical Sciences/Catalysis, Coke, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Chemical engineering, symbols, 0210 nano-technology, Raman spectroscopy, Cobalt
Abstract

The recyclability of a coked ethanol steam reforming catalyst (Co/Al2O3) is studied over several cycles. Oxidative regeneration burns coke, however some of the cobalt is oxidized. H2 produced during reforming promotes self-reactivation, restoring catalyst activity. The regeneration leads to the redispersion of smaller cobalt particles as a result of the Kirkendall effect.

Published
2018
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7. In situ XAFS Study of Palladium Electrodeposition at the Liquid/Liquid Interface

Author

Camille La Fontaine, Samuel G. Booth, Robert A. W. Dryfe, Giannantonio Cibin, Sven L. M. Schroeder, Akihiro Uehara, and Sin-Yuen Chang

Subjects
Materials science, General Chemical Engineering, Nucleation, Analytical chemistry, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, Chronoamperometry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, X-ray absorption fine structure, symbols.namesake, chemistry, Electrochemistry, symbols, Cyclic voltammetry, Absorption (chemistry), 0210 nano-technology, Raman spectroscopy, Palladium
Abstract

We report the use of XAFS (X-ray absorption fine structure) as an in situ method to follow the electrochemically driven deposition of palladium nanoparticles at a liquid/liquid interface. A novel glass/plastic hybrid electrochemical cell was used to enable control of the potential applied to the liquid/liquid interface. In situ measurements indicate that the nucleation of metallic nanoparticles can be triggered through chronoamperometry or cyclic voltammetry. In contrast to spontaneous nucleation at the liquid/liquid interface, whereby fluctuations in Pd oxidation state and concentration are observed, under a fixed interfacial potential the growth process occurs at a steady rate leading to a build-up of palladium at the interface. Raman spectroscopy of the deposit suggests that the organic electrolyte binds directly to the surface of the deposited nanoparticles. It was found that the introduction of citric acid results in the formation of spherical nanoparticles at the interface.

Published
2017
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8. ROCK: A Beamline Tailored for Catalysis and Energy-Related Materials from ms Time Resolution to µm Spatial Resolution

Author

Camille La Fontaine, Valérie Briois, Olga Roudenko, Laurent Barthe, Stéphanie Belin, Synchrotron SOLEIL (SOLEIL), Synchotron SOLEIL, and Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Materials science, Time resolution, Nanotechnology, 02 engineering and technology, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, Durability, Atomic and Molecular Physics, and Optics, Energy storage, Catalysis, Beamline, 0103 physical sciences, Data_FILES, 010306 general physics, 0210 nano-technology, Image resolution, Energy (signal processing), ComputingMilieux_MISCELLANEOUS
Abstract

Assessing the structure-activity relationship in materials used as catalysts or for energy storage is a major challenge in order to provide efficiency, durability, clean processes, and sustainable ...

Published
2020
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9. Operando X-ray absorption spectroscopy applied to battery materials at ICGM: The challenging case of BiSb's sodiation

Author

Valérie Briois, Romain Berthelot, Stéphanie Belin, Raphaël P. Hermann, Ali Darwiche, Marcus Fehse, Abdelfattah Mahmoud, Lorenzo Stievano, Antonella Iadecola, Bernard Fraisse, Fabrizio Murgia, Moulay Tahar Sougrati, Camille La Fontaine, Laure Monconduit, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), 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), Dutch Belgian Beam line (DUBBLE), European Synchrotron Radiation Facility (ESRF), Advanced Lithium Energy Storage Systems - ALISTORE-ERI (ALISTORE-ERI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Group of Research in Energy and ENvironment from MATerials (GREENMAT), Université de Liège, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Depart- ment of Energy. Synchrotron SOLEIL (France) is gratefully acknowledged for providing beamtime at the ROCK beamline., ANR-10-EQPX-0045,ROCK,Spectromètre EXAFS Rapide pour Cinétiques Chimiques(2010), European Project: 314515,EC:FP7:NMP,FP7-2012-GC-MATERIALS,EUROLIS(2012), European Project: 28721,ALISTORE, 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), European Synchroton Radiation Facility [Grenoble] (ESRF), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)

Subjects
X-ray absorption spectroscopy, Electrode material, Materials science, Absorption spectroscopy, Renewable Energy, Sustainability and the Environment, Energy Engineering and Power Technology, Nanotechnology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, 0104 chemical sciences, Electrochemical cell, Energy materials, General Materials Science, 0210 nano-technology
Abstract

X-ray absorption spectroscopy (XAS) is a synchrotron-based, element-specific, short-range structural method largely used in the study of materials, already widely employed for the study of the electrochemical processes in battery systems. The high penetration of the X-rays makes XAS particularly suited for the study of battery materials under operando conditions using specifically developed in situ electrochemical cells. In this paper, the application of XAS to the study of battery materials carried out at Institut Charles Gerhardt Montpellier (France) will be outlined, illustrating the type of information provided by XAS. The challenging study of the sodiation of Bi 0.50 Sb 0.50 followed individually and simultaneously at both metals will be also presented in order to highlight the typical advantages of this technique even when it is pushed at its technical limits.

Published
2019
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10. Tracing Active Sites in Supported Ni Catalysts during Butene Oligomerization by Operando Spectroscopy under Pressure

Author

Jörg Radnik, Stephan Peitz, Jabor Rabeah, Helene Reeker, Valérie Briois, Dietrich Maschmeyer, Angelika Brückner, Guido Stochniol, and Camille La Fontaine

Subjects
X-ray absorption spectroscopy, Absorption spectroscopy, 010405 organic chemistry, Chemistry, General Chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, Oxidative addition, Butene, Catalysis, Reductive elimination, 0104 chemical sciences, law.invention, Crystallography, chemistry.chemical_compound, Operando spectroscopy, law, Electron paramagnetic resonance
Abstract

Supported Ni catalysts have been studied during the dimerization of butenes by operando electron paramagnetic resonance (EPR) and in situ X-ray absorption spectroscopy (XAS) at 353 K and up to 16 bar. Single NiI/NiII shuttles were identified as active sites, whereby the conversion of initial NiI to NiII by oxidative addition of butene is obviously faster than the re-reduction of NiII to NiI by reductive elimination of the C8 product, rendering the equilibrium percentage of NiI small. At p ≤ 2 bar, NiI single sites form inactive Ni0 aggregates, while this is suppressed at higher pressure (∼12 bar). A reaction mechanism is proposed.

Published
2016
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11. The Electrochemical Sodiation of FeSb 2 : New Insights from Operando 57 Fe Synchrotron Mössbauer and X-Ray Absorption Spectroscopy

Author

Marcus Fehse, Lorenzo Stievano, Raphaël P. Hermann, Dimitrios Bessas, Laure Monconduit, Moulay Tahar Sougrati, Abdelfattah Mahmoud, Guy Rahamim, David Zitoun, Camille La Fontaine, Ali Darwiche, Advanced Lithium Energy Storage Systems - ALISTORE-ERI (ALISTORE-ERI), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Delft University of Technology (TU Delft), European Synchrotron Radiation Facility (ESRF), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), 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 de Liège, Bar-Ilan University [Israël], Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), European Project: 28721,ALISTORE, 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 Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
X-ray absorption spectroscopy, Materials science, Absorption spectroscopy, Analytical chemistry, Energy Engineering and Power Technology, chemistry.chemical_element, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Synchrotron, 0104 chemical sciences, law.invention, Amorphous solid, Antimony, chemistry, Electrochemical reaction mechanism, law, Mössbauer spectroscopy, Electrochemistry, Electrical and Electronic Engineering, 0210 nano-technology, Superparamagnetism
Abstract

International audience; Operando Sb K‐edge X‐ray absorption spectroscopy and 57Fe Synchrotron Mössbauer Spectroscopy, used for the first time in the field of operando energy storage materials, assisted by operando magnetic measurements, were combined to clarify the role of iron and antimony in the electrochemical reaction mechanism of FeSb2 as negative electrode material for sodium‐ion batteries (SIB). Both datasets were analyzed using an innovative chemometric approach involving principal component analysis (PCA) and multivariate curve resolution – alternating least square analysis (MCR‐ALS) yielding new insights on the sodiation reaction. Our findings show that the reaction of Na with FeSb2 during discharge leads to the formation of Na3Sb along with superparamagnetic Fe amorphous nanoparticles which contain small amounts of Sb dissolved in their lattice. During the following desodiation, the pristine material FeSb2 is not recovered while iron nanoparticles grow in size, and continue growing also along the following discharge. Even though such iron nanoparticles remain electrochemically inactive, they play a key role in the reduction and stabilization of the polarization as well as in the reversibility of the electrochemical sodiation of antimony.

Published
2019
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12. Iron speciation in iron–organic matter nanoaggregates: a kinetic approach coupling Quick-EXAFS and MCR-ALS chemometrics

Author

Mélanie Davranche, Jacques Jestin, Anthony Beauvois, Hélène Guénet, Valérie Briois, Camille La Fontaine, Rémi Marsac, Grace Campaore, Delphine Vantelon, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ANR-10-EQPX-45, Agence Nationale de la Recherche, ANR-10-EQPX-0045,ROCK,Spectromètre EXAFS Rapide pour Cinétiques Chimiques(2010), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)

Subjects
chemistry.chemical_classification, Materials Science (miscellaneous), Inorganic chemistry, 02 engineering and technology, 010501 environmental sciences, 021001 nanoscience & nanotechnology, 01 natural sciences, Oligomer, Metal, chemistry.chemical_compound, Hydrolysis, Ferrihydrite, chemistry, Polymerization, 13. Climate action, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, visual_art, visual_art.visual_art_medium, Humic acid, Organic matter, Metalloid, 0210 nano-technology, 0105 earth and related environmental sciences, General Environmental Science
Abstract

International audience; Iron–organic matter (Fe–OM) nanoaggregates are highly abundant in wetlands. Iron oxyhydroxides and natural OM are strong sorbents for metals and metalloids due to their high density of binding sites. They are thus considered as a major vector for the transport of metallic pollutants in this type of aquatic system. However, their structural organization is complex and varies under physico-chemical environmental conditions. The goal of this present study is to characterize these various iron phases and their growth processes. The formation of Fe-species was followed by Quick-EXAFS during oxidation/hydrolysis kinetics of pre-formed Fe(II)–humic acid complexes. Data were then processed using the MCR-ALS chemometric method. It demonstrated that, in the presence of OM, Fe(II) oxidation/hydrolysis leads to the synthesis of Fe-oligomers and ferrihydrite-like nanoparticles, both being bound to OM. The formation of the oligomers is the result of the inhibition of ferrihydrite polymerization by OM. Ferrihydrite and oligomers grow concomitantly during Fe(II) oxidation. When Fe(II) is completely oxidized, ferrihydrite forms at the expense of oligomers. For a given Fe/OM ratio, the ferrihydrite/oligomer ratio depends on the oxidation/hydrolysis kinetics which is strongly influenced by O2 and OH− availability. The organization of these structures constrains their binding site density and availability, which induces dramatic environmental implications regarding their capacity to trap metallic pollutants.

Published
2019
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13. Towards the synthesis of mixed oxides with controlled stoichiometry from Prussian blue analogues

Author

Jordan Dezalay, Cédric Baumier, Giulia Fornasieri, Patricia Beaunier, Camille La Fontaine, Anne Bleuzen, Amélie Bordage, Eric Rivière, R. Saint-Martin, Virgile Trannoy, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Réactivité de Surface (LRS), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Oxide, Nanoparticle, 02 engineering and technology, engineering.material, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, law.invention, chemistry.chemical_compound, law, Phase (matter), General Materials Science, Calcination, Prussian blue, Spinel, General Chemistry, Mesoporous silica, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Chemical engineering, chemistry, engineering, 0210 nano-technology, Stoichiometry
Abstract

International audience; Controlling the synthesis of mixed oxides is of great interest since their stoichiometry influences the properties. We present here the transformation of the Co4[Fe(CN)6]2.7 Prussian blue analogue (PBA) into the mixed Co1.8Fe1.2O4 spinel oxide, with a detailed characterization of the final phase (obtained by calcination in air at 900 °C for 2 hours) and an emphasis on the calcination process by TDA/TGA, X-ray diffraction, (high-resolution) TEM and energy-filtered TEM. Single-crystalline particles with a homogeneous distribution of Fe and Co ions within each particle are observed, with the same Co : Fe ratio as in the PBA. The calcination mechanism is a 2-step transformation, with first the elimination of water molecules and then the cyanide decomposition. XRD and TEM at intermediate temperatures additionally show the occurrence of a phase separation between 500 °C and 850 °C before the formation of the single final phase. We demonstrate also through the calcination of intermediate PBAs between Co4[Fe(CN)6]2.7 and Co4[Co(CN)6]2.7 that this synthesis route leads to the perfect control of the oxide stoichiometry through control of the PBA. The versatility of this synthesis route is finally illustrated through the successful synthesis of Co1.8Fe1.2O4 nanoparticles (diameter ∼5 nm) from PBA nanoparticles confined within the pores of a mesoporous silica monolith.

Published
2019
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14. The Electrochemical Sodiation of Sb Investigated by Operando X-ray Absorption and 121Sb Mössbauer Spectroscopy: What Does One Really Learn?

Author

Moulay Tahar Sougrati, Laure Monconduit, Raphaël P. Hermann, Marie-Liesse Doublet, Abdelfattah Mahmoud, Lorenzo Stievano, Bernard Fraisse, Mouna Ben Yahia, Ali Darwiche, Marcus Fehse, Camille La Fontaine, 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), European Synchroton Radiation Facility [Grenoble] (ESRF), Delft University of Technology (TU Delft), Advanced Lithium Energy Storage Systems - ALISTORE-ERI (ALISTORE-ERI), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Group of Research in Energy and ENvironment from MATerials (GREENMAT), Université de Liège, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Oak Ridge National Laboratory [Oak Ridge] (ORNL), UT-Battelle, LLC, Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), European Project: 28721,ALISTORE, Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), 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), Dutch Belgian Beam line (DUBBLE), European Synchrotron Radiation Facility (ESRF), Université de Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)

Subjects
Materials science, Absorption spectroscopy, Analytical chemistry, Energy Engineering and Power Technology, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, DFT calculations, 01 natural sciences, Na-ion batteries, Antimony, Ab initio quantum chemistry methods, Phase (matter), Mössbauer spectroscopy, lcsh:TK1001-1841, Electrochemistry, Electrical and Electronic Engineering, Absorption (electromagnetic radiation), X-ray absorption spectroscopy, [CHIM.MATE]Chemical Sciences/Material chemistry, alloy reaction, 021001 nanoscience & nanotechnology, chemometrics, 3. Good health, 0104 chemical sciences, Amorphous solid, lcsh:Production of electric energy or power. Powerplants. Central stations, MCR-ALS, chemistry, lcsh:Industrial electrochemistry, 0210 nano-technology, Sb, lcsh:TP250-261
Abstract

In this study, we want to highlight the assets and restrictions of X-ray absorption spectroscopy (XAS) and M&ouml, ssbauer spectroscopy for investigating the mechanism of the electrochemical reaction of antimony electrode materials vs. Na. For this, operando XAS was carried out during the first one and a half cycles, and the whole set of measured data was analysed using a statistical-chemometric approach, while low temperature M&ouml, ssbauer spectroscopy measurements were carried out ex situ on selected samples stopped at different points of the electrochemical reaction. Complementary ab initio calculations were performed to support the experimental findings. Both techniques show that, upon the first sodiation, most Sb reacts with Na to form disordered Na 3 Sb. This step is accompanied by the formation of amorphous Sb as an intermediate. Upon inversion of the current Na 3 Sb is desodiated and an amorphous Sb phase, distinct from the pristine bulk Sb state, is gradually formed. However, both XAS and M&ouml, ssbauer spectroscopy were unable to spot the formation of intermediate Na x Sb phases, which were evinced in previous works by operando Pair Distribution Function analyses. The results shown here clearly assign such failure to the intrinsic inability of both techniques to identify these intermediates.

Published
2018
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15. Isotopic niches and trophic levels of myctophid fishes and their predators in the Southern Ocean

Author

Jean-Philippe Labatc, Camille La Fontaine, Pierre Richard, Yves Cherel, Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Océanographie Biologique et Écologie du Plancton Marin (LOBEPM), Observatoire océanologique de Villefranche-sur-mer (OOVM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'Études Biologiques de Chizé (CEBC), LIttoral ENvironnement et Sociétés (LIENSs), and La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Electrona, Ecological niche, biology, Ecology, 010604 marine biology & hydrobiology, Niche segregation, Gymnoscopelus, Aquatic Science, Oceanography, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, Protomyctophum, Predation, Lanternfish, [SDE]Environmental Sciences, 14. Life underwater, Trophic level
Abstract

International audience; We report the trophic structure of a myctophid assemblage by measuring the isotopic niches of 14 species living in Kerguelen waters, southern Indian Ocean. Most of the species show distinct isotopic niches that differ by at least one of the two niche axes (d13C habitat and d15N trophic position), indicating trophic partitioning within the assemblage. Strong niche segregation occurs within each of the three most common genera of myctophids (Electrona, Gymnoscopelus, and Protomyctophum), illustrating the different mechanisms (habitat and dietary segregation) that allow coexistence of closely related species. Calculated trophic levels (TLs) of myctophids ranged from 3.3 to 4.2, showing that they are secondary and tertiary consumers in the pelagic ecosystem. The positive relationship between TL and standard length of fish points out a structuring effect of size, with larger species (Gymnoscopelus spp.) occupying a higher trophic position than smaller species (Krefftichthys anderssoni and Protomyctophum spp.). Myctophids occupy an intermediate trophic position between macrozooplanktonic crustaceans and seabirds and marine mammals within the pelagic ecosystem. However, the TLs of large myctophids overlap those of crustacean-eating seabirds [e.g., Eudyptes spp. (crested penguins) and Pachyptila belcheri]. The isotopic niche of myctophids indicates that Aptenodytes patagonicus (king penguin) adults prey upon K. anderssoni when they feed for themselves, thus exemplifying the usefulness of isotopic datasets on potential prey of predators to depict trophic relationships.

Published
2009
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16. Unusual behaviour of Au/ZnO catalysts in selective hydrogenation of butadiene due to the formation of a AuZn nanoalloy

Author

Catherine Louis, Laurent Delannoy, Salim Derrouiche, Gode Thrimurtulu, Sandra Casale, Camille La Fontaine, Hélène Lauron-Pernot, Laboratoire de Réactivité de Surface (LRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Hydrogen, Inorganic chemistry, High selectivity, Basic oxide, Alloy, chemistry.chemical_element, 02 engineering and technology, Zinc, [CHIM.CATA]Chemical Sciences/Catalysis, engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Catalysis, 0104 chemical sciences, Propene, chemistry.chemical_compound, chemistry, engineering, 0210 nano-technology
Abstract

International audience; The reaction of selective hydrogenation of butadiene performed in an excess of propene, which has been extensively studied over gold supported on different oxides and exhibited high selectivity to butenes, has been applied to the case of gold (1 wt%) supported on zinc oxide (8 m2 g−1), a strongly basic oxide, in order to try to thwart deactivation. Our results revealed, for the first time, a catalytic behaviour drastically different from what was previously observed over gold catalysts supported on alumina or titania, i.e. a much poorer activity when the catalyst was activated under usual conditions under hydrogen but a “normal” activity when it was activated in air. An in-depth characterisation study based on different hypotheses to explain the unusual result revealed that at variance with the other catalysts, Au1Zn1 alloy particles formed during activation under hydrogen at 300 °C and were responsible for the loss of activity.

Published
2016
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17. Speciation of Ruthenium as a Reduction Promoter of Silica-Supported Co Catalysts: A Time-Resolved in Situ XAS Investigation

Author

Eric Marceau, Andrei Y. Khodakov, Valérie Briois, Anne Griboval-Constant, Lucia Gaberova, Camille La Fontaine, Jingping Hong, Jean-Sébastien Girardon, Kyung Hee University (KHU), Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre d'Ecologie et des Sciences de la COnservation (CESCO), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, and Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)

Subjects
Inorganic chemistry, chemistry.chemical_element, Nanoparticle, 02 engineering and technology, 010402 general chemistry, Fischer−Tropsch synthesis, 01 natural sciences, Catalysis, law.invention, Metal, law, [CHIM]Chemical Sciences, Calcination, ruthenium, X-ray absorption spectroscopy, Fischer–Tropsch process, General Chemistry, 021001 nanoscience & nanotechnology, in situ study, cobalt, 0104 chemical sciences, Ruthenium, reduction promoter, chemistry, visual_art, visual_art.visual_art_medium, 0210 nano-technology, Cobalt
Abstract

International audience; Complete reduction of the metal phase in cobalt-containing catalysts is often difficult to reach and can be promoted by a small amount of noble metals. Because these costly promoters are introduced in a very low quantity, their speciation and their chemical interaction with cobalt have seldom been studied in detail. We present here a time-resolved in situ X-ray absorption spectroscopy investigation of the speciation of ruthenium, used as a reduction promoter of cobalt, throughout the preparation of Co/SiO2 catalysts. In the cobalt(II) nitrate impregnation solution, ruthenium is detected as hydrated Ru(OH)4 short-chain oligomers that are deposited on silica upon drying. Co3O4 forms during calcination in air and catalyzes the elimination in the gas phase of 60% of Ru. The addition of a polyol, sorbitol, in the impregnation solution stabilizes the whole of Ru on the catalyst. Upon calcination, Ru(IV) ions are inserted inside Co3O4 nanoparticles. Reduction of the oxidic phase takes place in two distinct steps, at approximately the same temperatures regardless of the ruthenium content: first to Ru(III)-containing CoO nanoparticles (Ru ions modifying the intrinsic electronic properties of the oxidic nanoparticles); then to bimetallic Co nanoparticles containing Ru(0) atoms, via an autocatalytic process. Ru loadings as low as 0.2 wt % are sufficient to afford complete reduction of cobalt. Close association between Ru and Co from the beginning of the synthesis is thus necessary for a maximum promoting effect

Published
2015
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18. Key Features of Intertidal Food Webs That Support Migratory Shorebirds

Author

Julien Chalumeau, Johann Lavaud, Katell Guizien, Gilles Radenac, Gwenaël Quaintenne, Pierre Richard, Alain F. Vézina, Pierre-Yves Pascal, Pierrick Bocher, Christine Dupuy, Hélène Montanié, Margot De Crignis, Sébastien Lefebvre, Blanche Saint-Béat, Nathalie Niquil, Frédéric Robin, Jean-Luc Mouget, Camille La Fontaine, Francis Orvain, LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Lab-STICC_CNRS_CID_SFIIS, Département Image et Traitement Information (ITI), Université européenne de Bretagne - European University of Brittany (UEB)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT)-Université européenne de Bretagne - European University of Brittany (UEB)-Télécom Bretagne-Institut Mines-Télécom [Paris] (IMT)-Laboratoire des sciences et techniques de l'information, de la communication et de la connaissance (Lab-STICC), Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Ecogéochimie des environnements benthiques (LECOB), Observatoire océanologique de Banyuls (OOB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Mer, molécules et santé EA 2160 (MMS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN), Biologie des mollusques marins et des écosystèmes associés (BioMEA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de biologie et environnement marins - LBEM (LBEML), Normandie Université (NU), Centre d'Études Biologiques de Chizé (CEBC), Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS), Bedford Institute of Oceanography, Fisheries and Oceans Canada (DFO), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Télécom Bretagne-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université européenne de Bretagne - European University of Brittany (UEB)-École Nationale Supérieure de Techniques Avancées Bretagne (ENSTA Bretagne)-Institut Mines-Télécom [Paris] (IMT)-Centre National de la Recherche Scientifique (CNRS)-École Nationale d'Ingénieurs de Brest (ENIB)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Université de Nantes (UN)-Université de Nantes (UN)-Le Mans Université (UM)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université du Littoral Côte d'Opale-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Le Mans Université (UM)-Université de Nantes - UFR des Sciences Pharmaceutiques et Biologiques, Centre interdisciplinaire de recherche, culture, éducation, formation, travail (CIRCEFT), and Université Paris 8 Vincennes-Saint-Denis (UP8)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)

Subjects
0106 biological sciences, [SDV.BIO]Life Sciences [q-bio]/Biotechnology, lcsh:Medicine, [SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy, 01 natural sciences, Nest, Flyway, lcsh:Science, Atlantic Ocean, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Biomass (ecology), Multidisciplinary, geography.geographical_feature_category, Geography, Ecology, [SDV.BV.BOT]Life Sciences [q-bio]/Vegetal Biology/Botanics, Food web, Markov Chains, Bays, [SDE]Environmental Sciences, France, Seasons, Monte Carlo Method, Research Article, Food Chain, [SDE.MCG]Environmental Sciences/Global Changes, Intertidal zone, Biology, 010603 evolutionary biology, Models, Biological, [SDV.MP.PRO]Life Sciences [q-bio]/Microbiology and Parasitology/Protistology, Birds, Animals, Ecosystem, 14. Life underwater, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Shore, geography, Bacteria, 010604 marine biology & hydrobiology, lcsh:R, 15. Life on land, Invertebrates, lcsh:Q, Animal Migration, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Bay, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract

International audience; The migratory shorebirds of the East Atlantic flyway land in huge numbers during a migratory stopover or wintering on the French Atlantic coast. The Brouage bare mudflat (Marennes-Oléron Bay, NE Atlantic) is one of the major stopover sites in France. The particular structure and function of a food web affects the efficiency of carbon transfer. The structure and functioning of the Brouage food web is crucial for the conservation of species landing within this area because it provides sufficient food, which allows shorebirds to reach the north of Europe where they nest. The aim of this study was to describe and understand which food web characteristics support nutritional needs of birds. Two food-web models were constructed, based on in situ measurements that were made in February 2008 (the presence of birds) and July 2008 (absence of birds). To complete the models, allometric relationships and additional data from the literature were used. The missing flow values of the food web models were estimated by Monte Carlo Markov Chain – Linear Inverse Modelling. The flow solutions obtained were used to calculate the ecological network analysis indices, which estimate the emergent properties of the functioning of a food-web. The total activities of the Brouage ecosystem in February and July are significantly different. The specialisation of the trophic links within the ecosystem does not appear to differ between the two models. In spite of a large export of carbon from the primary producer and detritus in winter, the higher recycling leads to a similar retention of carbon for the two seasons. It can be concluded that in February, the higher activity of the ecosystem coupled with a higher cycling and a mean internal organization, ensure the sufficient feeding of the migratory shorebirds.

Published
2013
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19. Synergy between XANES spectroscopy and DFT to Elucidate the Amorphous Structure of Heterogeneous Catalysts: TiO2-Supported Molybdenium Oxide Catalysts

Author

Asma Tougerti, Anne-Sophie Mamede, Yves Joly, Camille La Fontaine, Jean-François Paul, Elise Berrier, Sylvain Cristol, Edmond Payen, Valérie Briois, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Surfaces, Interfaces et Nanostructures (NEEL - SIN), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-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), Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Surfaces, Interfaces et Nanostructures (SIN), Laboratoire de catalyse de Lille - UMR 8010 (LCL), and Université de Lille, Sciences et Technologies-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)

Subjects
X-ray absorption spectroscopy, XANES Spectroscopy, Heterogeneous catalysis, 010405 organic chemistry, Chemistry, Inorganic chemistry, Molybdenum oxide, chemistry.chemical_element, General Medicine, General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Amorphous solid, Ab initio quantum chemistry methods, Molybdenum, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2013
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20. Silver species reduction upon exposure of Ag/Al2O3 catalyst to gaseous ethanol: An in situ Quick-XANES study

Author

Dalil Brouri, Pascale Massiani, Valérie Briois, Elie Sayah, Camille La Fontaine, Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), and Centre National de la Recherche Scientifique (CNRS)

Subjects
Inorganic chemistry, 02 engineering and technology, Thermal treatment, 010402 general chemistry, 01 natural sciences, SCR catalysis, Catalysis, chemistry.chemical_compound, Reduction, Ethanol, X-ray absorption spectroscopy, Selective catalytic reduction, General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, XANES, UV-visible spectroscopy, 0104 chemical sciences, Boiling point, chemistry, Transmission electron microscopy, In situ Quick-XANES, Absorption (chemistry), Silver nanoparticles, 0210 nano-technology
Abstract

International audience; The evolution of supported silver species of a pre-calcined Ag/Al2O3 catalyst was monitored upon thermal treatment under an air flow enriched with 3000 ppm of ethanol (EtOH) using transmission electron microscopy and UV-visible and X-ray absorption spectroscopies. A special focus is put on the application of in situ Quick-XAS that permits to acquire high quality spectra at the Ag K-edge with a good time resolution (30 s), thus informing in real time on the transformations of the silver species. While the reduction of silver under Air/EtOH flow is shown to possibly occur at room temperature, the process is strongly accelerated by heating, most of the silver being indeed reduced at ca. 78 °C, a temperature which corresponds to the ethanol boiling point. The possible impact of this silver sensitivity on the behavior of silver-alumina catalysts in reactions such as the selective catalytic reduction (SCR) of NOx in presence of ethanol is addressed.

Published
2012
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21. XANES study of rhenium oxide compounds at theL1andL3absorption edges

Author

Françoise Villain, Asma Tougerti, Camille La Fontaine, Valérie Briois, Elise Berrier, Sylvain Cristol, and Yves Joly

Subjects
Materials science, Rhenium oxide, Ab initio, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Spectral line, XANES, 3. Good health, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Local symmetry, Oxidation state, Cluster size, Physical chemistry, 0210 nano-technology, Absorption (electromagnetic radiation)
Abstract

We report on the study of a set of rhenium oxide reference compounds (NH4ReO4, NaReO4, ReO3, ReO2, and Re2O7) using x-ray-absorption near-edge structure. The parallel use of Re L1 and L3 absorption edges permits a concomitant understanding of both the oxidation state and the local symmetry for these compounds. Experiments are compared with ab initio simulations. A good agreement is reached in most cases. The choice of the cluster size and the calculation method (full potential or not), which are mandatory ingredients allowing a satisfactory reproduction of the recorded spectra, is discussed in detail. In the meantime, these parameters give important pieces of information on the studied materials.

Published
2012
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22. A Time-Resolved In Situ Quick-XAS Investigation of Thermal Activation of Fischer-Tropsch Silica-Supported Cobalt Catalysts

Author

Eric Marceau, Jingping Hong, Camille La Fontaine, Anne Griboval-Constant, Andrei Y. Khodakov, Valérie Briois, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), and Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille

Subjects
In situ, Reaction mechanism, Inorganic chemistry, chemistry.chemical_element, 010402 general chemistry, Heterogeneous catalysis, 01 natural sciences, Catalysis, time-resolved spectroscopy, supported catalysts, ComputingMilieux_MISCELLANEOUS, X-ray absorption spectroscopy, 010405 organic chemistry, Chemistry, Organic Chemistry, Fischer–Tropsch process, General Chemistry, Cobalt, [CHIM.CATA]Chemical Sciences/Catalysis, Silicon Dioxide, Fischer-Tropsch reaction, 0104 chemical sciences, reaction mechanisms, X-Ray Absorption Spectroscopy, heterogeneous catalysis, Models, Chemical, cobalt hydroxynitrate, Time-resolved spectroscopy
Abstract

International audience

Published
2012
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23. Impact of sorbitol addition on the structure and performance of silica-supported cobalt catalysts for Fischer-Tropsch synthesis

Author

Camille La Fontaine, Valérie Briois, Françoise Villain, Jingping Hong, Eric Marceau, Anne Griboval-Constant, Andrei Y. Khodakov, Petr A. Chernavskii, Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire pour l'utilisation du rayonnement électromagnétique (LURE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-MENRT-Centre National de la Recherche Scientifique (CNRS), Moscow State University, Department of Chemistry, Moscow State University, and Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille

Subjects
inorganic chemicals, Thermogravimetric analysis, Inorganic chemistry, chemistry.chemical_element, Thermal treatment, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, Propene, chemistry.chemical_compound, Cobalt catalysts, Sorbitol, Temperature-programmed reduction, Cobalt oxide, 010405 organic chemistry, Fischer–Tropsch process, Silica, General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, Fischer-Tropsch synthesis, 0104 chemical sciences, chemistry, Quick-XAS, Cobalt
Abstract

International audience; The paper focuses on the impact of sorbitol addition on the genesis of cobalt active phases in silica-supported catalysts and on their performance in Fischer-Tropsch synthesis. The catalysts were characterized by ex situ and in situ diffuse reflectance spectroscopy in the ultraviolet and visible regions, differential thermal and thermogravimetric analyses combined with mass spectroscopy, in situ Quick-X-ray absorption, X-ray diffraction, H2-temperature programmed reduction, in situ magnetic measurements and propene chemisorption. Sorbitol retards the decomposition of cobalt ionic complexes into Co3O4 during thermal treatment in air, leading to higher cobalt oxide dispersion. The smaller cobalt oxide particles in sorbitol-derived samples exhibit a much lower reducibility than those prepared without the additive. Fischer-Tropsch reaction rate is proportional to the number of cobalt metal sites, which is a function of both cobalt dispersion and cobalt reducibility. It depends in a complex manner on the initial sorbitol content.

Published
2011
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24. Investigation of different preparation methods of PtIr, PtIrSn and PtIrGe catalysts

Author

Christophe Poupin, Laurence Pirault-Roy, Camille La Fontaine, Unité de Chimie Environnementale et Interactions sur le Vivant (UCEIV), Université du Littoral Côte d'Opale (ULCO), Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Institut de Chimie du CNRS (INC), and Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Inorganic chemistry, chemistry.chemical_element, Germanium, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Grafting, 01 natural sciences, 0104 chemical sciences, Catalysis, Preparation method, chemistry, Iridium, 0210 nano-technology, Tin, Platinum, ComputingMilieux_MISCELLANEOUS
Abstract

Addition of Ir to a Pt/Al 2 O 3 catalyst by two different methods, successive impregnation and organometallic grafting resulted in catalysts with different structure: in the first case separate Pt and Ir sites can be suggested, while in the second case, Ir was exclusively deposited on Pt, forming very small Ir clusters on Pt particles. Addition of Ge or Sn to the Pt-Ir grafted catalyst led to third component deposit on the surface of mixed metals particles. On the other hand, when the promoter is added to PtIr-IS, Ge seems to be located on Ir particles while Sn modified Pt particles.

Published
2010
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25. Exhaust gas recirculation for on-board hydrogen production by isooctane reforming: Comparison of performances of metal/ceria-zirconia based catalysts prepared through pseudo sol-gel or impregnation methods are described

Author

Séverine Rousseau, Claire Courson, Camille La Fontaine, Françoise Villain, Emmanuelle Ambroise, Gilbert Blanchard, Xavier Carrier, Anne-Cécile Roger, Alain Kiennemann, Eric Marceau, Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse (LMSPC), Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences 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)-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), PSA Peugeot Citroën, PSA Peugeot Citroën (PSA), Laboratoire de Réactivité de Surface (LRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-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)

Subjects
metal ceria zirconia catalyst impregnation, Hydrogen, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, General Chemistry, exhaust gas recirculation hydrogen isooctane reforming, [CHIM.CATA]Chemical Sciences/Catalysis, engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, Heterogeneous catalysis, 7. Clean energy, 01 natural sciences, Catalysis, 0104 chemical sciences, Transition metal, chemistry, engineering, Noble metal, Cubic zirconia, 0210 nano-technology, Bimetallic strip, Hydrogen production
Abstract

52-1 FIELD Section Title:Electrochemical, Radiational, and Thermal Energy Technology 67 Laboratoire des Materiaux, Surfaces et Procedes pour la Catalyse (UMR 7515 CNRS), Universite de Strasbourg, Strasbourg, Fr. FIELD URL: written in English; Isooctane reforming under conditions which are set by exhaust gas can be used to generate H on-board. Isooctane reforming reactivity tests have been performed with bimetallic catalysts Co-noble metal/ceria-zirconia, prepd. either by insertion of transition metal in a ceria-zirconia matrix, either by their impregnation on ceria-zirconia. The influence of the prepn. procedure on the activity of the noble metal-doped catalysts is discussed. [on SciFinder(R)]

Published
2010
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26. Tissue, ontogenic and sex-related diVerences in 13C and 15N values of the oceanic squid Todarodes Wlippovae (Cephalopoda: Ommastrephidae)

Author

George D. Jackson, Christine H. Jackson, Pierre Richard, Yves Cherel, Camille La Fontaine, Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS), Institute of Antarctic and Southern Oceanic Studies [Horbat] (IMAS), University of Tasmania [Hobart, Australia] (UTAS), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), and Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Squid, Ecology, δ13C, 010604 marine biology & hydrobiology, Ontogeny, [SDE.MCG]Environmental Sciences/Global Changes, Zoology, Aquatic animal, Aquatic Science, Biology, biology.organism_classification, 010603 evolutionary biology, 01 natural sciences, [SDE.ES]Environmental Sciences/Environmental and Society, Sexual dimorphism, biology.animal, Ommastrephidae, 14. Life underwater, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Mollusca, Ecology, Evolution, Behavior and Systematics, Trophic level
Abstract

International audience; Stable isotopes are increasingly used in the study of trophic interactions of many aquatic animals and most recently cephalopods. To evaluate the application of the method to squids, it is important to assess isotopic diVerences among and within consumer tissues that may confound the resolution of ecological relationships. Interand intra-tissue isotopic variation was examined in 55 individuals of the oceanic squid Todarodes Wlippovae that were collected at the beginning of April 2000 in the southwestern Indian Ocean (between 44°S, 76°E, and Saint Paul and Amsterdam islands, 38°S, 78°E). Delipidated soft tissues (mantle, arm, buccal mass, gill and reproductive organs) showed small 13C and 15N diVerences, which were probably tissue-speciWc. A lower carbon value was observed in the digestive gland as a consequence of incomplete lipid removal. Hard tissues, such as beaks and gladii, had lower 15N values than soft tissues, which can be explained by the presence of chitin, a 15N-depleted molecule. Females (n = 38) and males (n = 17) had identical 13C values, but females showed higher 15N values than males. The diVerence was size-related rather than sex-related, however, as females were generally larger than males. A comparison of similar-sized females and males produced identical nitrogen values. These data suggest dietary shifts from lower to higher trophic levels during growth, because 15N values of large T. Wlippovae were much higher than that of small specimens. As expected, nitrogen values of lower beaks and gladii of large squids increased from the oldest to the most recently formed region, reXecting the progressive growth of chitinized tissues in parallel with dietary changes. Sequential sampling along the growth increments of squid beaks and gladii can likely be used to produce a chronological record of dietary information throughout an individual's history.

Published
2009
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27. Stable isotopes reveal the trophic position and mesopelagic fish diet of female southern elephant seals breeding on the Kerguelen Islands

Author

Christophe Guinet, Pierre Richard, Yves Cherel, Camille La Fontaine, Simon Ducatez, Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur les Ecosystèmes Littoraux Anthropisés (CRELA), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
0106 biological sciences, Mesopelagic zone, [SDE.MCG]Environmental Sciences/Global Changes, Aquatic Science, Pelagic ecosystem, 010603 evolutionary biology, 01 natural sciences, Cephalopod, Predation, 14. Life underwater, Colossal squid, Southern Ocean, Squid, Ecology, Evolution, Behavior and Systematics, Trophic level, Mesopelagic fish, Polar front, Ecology, biology, 010604 marine biology & hydrobiology, Cephalopod · Mesopelagic fish · Myctophid · Pelagic ecosystem · Southern Ocean · Squid, biology.organism_classification, [SDE.ES]Environmental Sciences/Environmental and Society, Southern elephant seal, 13. Climate action, Guild, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, Myctophid
Abstract

Trophic interactions between organisms are the main drivers of ecosystem dynamics, but scant dietary information is available for wide-ranging predators during migration. We investigated feeding habits of a key consumer of the Southern Ocean, the southern elephant seal Miroungia leonina, by comparing its blood delta(13) C and delta N-15 values with those of various marine organisms, including crustaceans, squid, fishes, seabirds and fur seals. At the end of winter, delta C-13 values (-23.1 to -20.1 parts per thousand)indicate that female elephant seals forage mainly in the vicinity of the Polar Front and in the Polar Frontal Zone. Trophic levels derived from delta N-15 values (trophic level = 4.6) show that the southern elephant seal is a top consumer in the pelagic ecosystem that is dominated by colossal squid. The mean delta N-15 value of seals (10.1 +/- 0.3 parts per thousand) indicates that they are not crustacean eaters, but instead feed on crustacean-eating prey. Surprisingly, most of the previously identified prey species have isotope delta C-13 and delta N-15 values that do not fit with those of potential food items. The most singular pattern to emerge from delta N-15 values of predators and prey is that female seals are likely to feed on myctophid fishes, not squid or Patagonian toothfish. We therefore suggest that they Occupy a unique trophic niche amongst the guild of air-breathing, diving vertebrates by feeding on mesopelagic fish at great depths. In turn, this finding emphasizes the role of myctophids in oceanic waters and will help to quantify and model fluxes of matter and energy within the pelagic ecosystem of the Southern Ocean.

Published
2008
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28. Well-defined Rh/Al2O3 catalysts selectively poisoned by Ge: a new tool to study reaction pathways

Author

Laurence Pirault-Roy, Camille La Fontaine, Charles Kappenstein, Irina Boghian, Centre d'Ecologie et des Sciences de la COnservation (CESCO), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Institut de Chimie du CNRS (INC), Laboratoire de catalyse en chimie organique (LACCO), Université de Poitiers-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Chemistry, Inorganic chemistry, chemistry.chemical_element, Infrared spectroscopy, Germanium, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, Heterogeneous catalysis, 01 natural sciences, 010406 physical chemistry, 0104 chemical sciences, Catalysis, Rhodium, Transition metal, Chemisorption, Bimetallic strip, ComputingMilieux_MISCELLANEOUS
Abstract

Alumina-supported rhodium catalysts (1 wt.-% Rh) have been modified by surface organometallic reaction using tetra-n-butylgermanium in an in situ specifically designed reactor. Two parent Rh/Al 2 O 3 samples have been used with metal dispersion of 80 and 20 % and bimetallic catalysts have been prepared by Ge introduction in the range of 1/20 to 2 monolayers. The samples have been characterized by H 2 chemisorption, TEM, electron diffraction and infrared spectroscopy of adsorbed CO probe molecules. A moderate amount of grafted Ge leads to a selective deposit of the additive to high-coordination rhodium sites present on the faces whereas an important amount of germanium induces the formation of bulk Ge-Rh phases as Ge 3 Rh 5 .

Published
2006
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